False-positive Collision between Eye-Ray and Capsule Collider

I have a key on the origin, which can be pointed towards 12 clock points on the XZ plane, or straight upwards:


The key has a capsule collider, so I can check when the user clicks on it:

 void Update( )
 {
     if( Input.GetMouseButtonDown( 0 ) ) 
         tryTouchPoint( Input.mousePosition );
 }


 void tryTouchPoint( Vector3 p ) 
 {
     Ray ray = Camera.main.ScreenPointToRay( p );

     RaycastHit hitResult;

     if( key.collider.Raycast( ray, out hitResult, 1000.0f ) )
     {
         Debug.DrawLine (ray.origin, hitResult.point);
         Debug.Break();
         :
     }

It does correctly register on-target clicks.

However, it is possible to create a situation where it also registers false positives: a ray that clearly misses the capsule can trigger a collision.

It's easiest to show it in a video: http://screencast.com/t/QNMQodecGnV0

EDIT: Complete key rotation code here:

// http://forum.unity3d.com/threads/54720-Gold-texture-on-iphone

 using UnityEngine;
 using System.Collections;

 public class KeyScript : MonoBehaviour 
 {
     public int currKey;
     
     float tKeyChange;
     
     float xRot = 0f, yRot = 0f, zRot = 0f;

     enum Status { Idle, Spinning, Transitioning };
     Status m_status = Status.Idle;

     // better than doing FindObjectOfType(typeof(X)) from client
     static public KeyScript singleInstance;
     void Awake( ) {
         singleInstance = this;
         newQuat = Quaternion.identity;
         m_status = Status.Idle;
         currKey = -1;
     }
     
     public bool isSpinning { get { return m_status == Status.Spinning; } }

 //    public void Toggle( ) {
 //        if( m_status == Status.Spinning )
 //            m_status = Status.Idle;
 //        else
 //            m_status = Status.Spinning;
 //    }

     public void Spin( )
     {
         m_status = Status.Spinning;
     }

     Quaternion oldQuat, newQuat;

     // Update is called once per frame
     void Update () 
     {
 //        float scale = Wheel.btnScale / 9.0f;
 //        
 //        transform.localScale = new Vector3( scale, scale, scale );

         switch( m_status )
         {
         case Status.Idle:
             break;

         case Status.Spinning:
             float rotSpeed = 60f;
             xRot += Time.deltaTime * rotSpeed;
             while( xRot > 360f )
                 xRot -= 360f;
             transform.rotation = ConstructRot( xRot, yRot, zRot );
             break;

         case Status.Transitioning:
             float t = Mathf.InverseLerp( tKeyChange, tKeyChange + 0.3f, Time.time );

             Quaternion foo = Quaternion.Slerp( oldQuat, newQuat, t );

             if( t == 1f )
                 m_status = Status.Idle;

             transform.rotation = foo;
             break;
         }
     }

     public void SetKey( int k )
     {
         m_status = Status.Transitioning;
         tKeyChange = Time.time;
         currKey = k;

         if( k == -1 )
         {
             xRot = 0f;
             yRot = 0f;
             zRot = 90f;
         }
         else{
             xRot = 0f;
             yRot = 360f * (float)(k-0f) / 12f;
             zRot = 0f;
         }

         oldQuat = transform.rotation;
         newQuat = ConstructRot( xRot, yRot, zRot );
     }


     Quaternion ConstructRot( float xRot, float yRot, float zRot )
     {
         Quaternion firstXRot = Quaternion.AngleAxis( xRot, Vector3.forward );
         Quaternion nowYRot = Quaternion.AngleAxis( yRot, Vector3.up );
         Quaternion finallyZRot = Quaternion.AngleAxis( zRot, Vector3.right );

         return finallyZRot * ( nowYRot * firstXRot );
     }
 }

EDIT: Main code:

 void Update( )
 {
     float secs_per_frame = Time.deltaTime;
     float fps = 1f / secs_per_frame;
     
     fps_smooth = Mathf.Lerp( fps_smooth, fps, 0.1f );
     
     CheckForUserInput( );
 }
 
 
 void CheckForUserInput( ) 
 {
     
     // mouse L button    
     if( Input.GetMouseButtonDown( 0 ) ) 
         tryTouchPoint( Input.mousePosition );
 }


 void OnGUI( )
 {
     if( GUILayout.Button( "BUG" ) )
         fail();
 }

 void fail()
 {
     RaycastHit hitResult;

     key.gameObject.transform.rotation = new Quaternion(0.7071068f,0f,0f,0.7071068f);

     Ray ray = new Ray( 
                       new Vector3(0.03398795f, 9.7f, -0.05699179f) , 
                       new Vector3(0.1106194f, -0.9764f, -0.1854893f)
                       );

     if( key.collider.Raycast( ray, out hitResult, 1000.0f ) )
         Debug.Log( "Got teh bug!" );
     else
         Debug.Log( " no collision wtf " );
 }

 void tryTouchPoint( Vector3 p ) 
 {
     Ray ray = Camera.main.ScreenPointToRay( p );

     Debug.DrawLine( ray.origin, ray.origin + (ray.direction * 1024f) );

     RaycastHit hitResult;

     if( key.collider.Raycast( ray, out hitResult, 1000.0f ) )
     {
         //if( ! key.isSpinning )
         Quaternion Q = key.gameObject.transform.rotation;
         Vector3 O = ray.origin, D = ray.direction;

         string LogString = string.Format( "Quaternion: ({0}f, {1}f, {2}f, {3}f), Ray Origin: ({4}f, {5}f, {6}f), Ray Direction: ({7}f, {8}f, {9}f)",
                   Q.x, Q.y, Q.z, Q.w,
                   O.x, O.y, O.z,
                   D.x, D.y, D.z
                   );
                  
         Debug.Log( LogString );


         if( key.isSpinning ) SetKey( -1 ); 
         else key.Spin( );

         return;
     }

     float dWinner = 1234567;
     int winner = 0;
     for( int i=0; i < allGems.Length; i++ )
     {
         GlowGem G = allGems[ i ];

         float dist = DistBetween( ray, G.transform.position );

         if( dist < dWinner )
         {
             dWinner = dist;
             winner = i;
         }
     }

     if( dWinner < 1f ) 
     {
         if( key.isSpinning ) {
             SetKey( winner );
         }
         else {
             allGems[ winner ].UserHit( );
     
             if( noteHit_User_Event != null )
                 noteHit_User_Event( winner );
         }
     }
 }
 
 void SetKey( int k )
 {
     key.SetKey( k );

     //float [] s = new float[] { 10,3,7,3,7,7,3,7,3,7,3,7 };

     for( int deg=0; deg < 12; deg++ ) { // scale degree; 0 is tonic etc
         //float size = ( k == -1 ) ? 0.8f : new float[] { 10,3,7,3,7,7,3,7,3,7,3,7 }[ deg ] / 10f;
         int toneme = ( k == -1 ) ? deg : ( k + deg ) % 12; // offset from keynote

         allGems[ toneme ].SetDegree ( ( k == -1 ) ? 2 : deg );
     }

     if( k > -1 )
         allGems[ k ].UserHit( );
 }

[1]: /storage/temp/22972-screen+shot+2014-03-02+at+16.55.35.png