Everyone that has been using the native client since day 1 has never had one of these so called collisions. It just hasn't happened. You have more chances of getting hit by an asteroid tomorrow during your commute to your job than you'll ever have chances to get a legitimate collision, literally speaking.
Well, sometimes it does go deeper than your own code:
https://bitcoin.org/en/alert/2013-08-11-android
Either way, if a user comes across such a "collision" they should definitely report it -- albeit rather by contacting the devs directly instead of posting on a public forum.
Also I will now blame you for my newfound phobia of rocks falling from the sky.
Look, there is the android RNG problem you mention, there was a similar one that enabled the Sony playstation hack, there are others. A dysfunction random number gen is a direct enabler of back door entry and of password decryption.
In practice there isn't any difference between active insertion of defective RNG and accidental actions as the end result is the same, an insecure system capable of being successfully attacked.
An address with funds in it on loading a wallet is glaring evidence of the existence of a problem with the wallet, but not of the cryptographic system.
Ah, sorry, I guess that came out wrong.
I merely wanted to point out that sometimes the error lies beyond the scope of the application developer, ie. your software can still fall victim to a vulnerability without your code being shit. In either case it should be reported because best case the application has a problem, worst case its the platform's -- or the used crypto library's -- fault.
I didn't mean to imply that Bitcoin's keyspace is even remotely small enough for a collision to occur.