Instead of expecting other people to be evil doers that want to break your system. Think of them as nice people that want to make it better for everyone, including you! As they are nice people they might make an oversight (and admit it), and they will be thrilled if you kindly pointed out an edge case and ask if it hasn't been covered.
Or more clearly, drop the hostile usability remarks. It is the daily work of many (even hackers) and many take great pride in helping others.