if you flash it through cwm, it cannot be uninstalled. also, since the app can be fully hidden, most people would not even suspect the app to be installed. and how many people do you think are capable of flashing another rom and fully wiping the phone?
most regular phone users don't even update their phone through kies and people who get their hand on the phone and have no idea about android at all certainly would never get the idea.
they would be too stupid to get over pattern lock in the first place, and by then, you will have their picture, their location and have sound recorded of them, which should be enough for the police to get your phone back.
for the meantime lock the device down completely and/or wipe it and even if the device is not connected to the internet, just with gsm signal you can still fully control it through sms. if you are still not able to get it back, get the imei blocked and the phone will be useless to any thief.
in any way, i love cerberus and never felt safer with my sgs2.