Unity Player force close on Android

During the alpha test of our game, we distributed it to ~70 people. Of all the different devices, only one of them fails to run the game, and the entire Unity Player process crashes on it with a force close dialog box. The phone in question is a Samsung Note 4 running Android 4.4.4. As luck would have it, it's the CEO's phone ( Murphy's law says hi :| ), and we have no means of accessing it directly whatsoever. This leaves us with two questions:

1. Why would the Player crash at all? We're not using any native (C++ or Java) plugins, only C# code, and since C# runs under a VM, it's unlikely to crash the native process. We do have external C# libraries included in the project, and those create network threads of their own. Could this be a cause for the crash?

2. Since we have no direct access to the device and logcat is out of the question, how should we trace the error to find its source? Is there some way to dump the app's logs to a file or something which we can then recover?

Any help is greatly appreciated.