Rehabilitation of cheaters.

BLUR, I'll answer you this way - if you can't figure out how to check whether your opponent is cheating, just don't think about it at all.
Focus on your own game, develop your strategy, and prioritize what's important to you in life.
Assume that your opponents are not cheating.
If you keep learning how to play Heroes, the answers will come to you.
There is no definitive answer to your question - you need to pay close attention and think critically in each specific situation.

P.S. If you are a cheater and are just testing the waters, the answer is this: in your example, it's impossible to catch. And in real life, the optimal solution is to rob a bank.