Engine assistance? (Cheaters)

How do I know for certain if someone is not using Engine assistance in a 5 minute blitz game? The only reason I limit myself to playing 3 minute blitz games on Chess.com is because of the fact that anything more than 3 minutes is enough of a timeframe for a cheater to use engine assistance throughout the game. I've had my suspicions, but can never know for sure.

in 3 minute games, I played an idiot who would spend exactly 7-8 seconds per move, even in the most obvious theoritical lines, and pre-move positions. I was pretty sure he was cheating, but I managed to win that game on time because he was stupid enough to not speed up his moves.

Does Chess.com really do anything to montor this cheating in real time? I know that chesscube.com has a system where if you keep minizming your window, an automated warning pops up on your screen asking you to not do so, and if you continue switching windows, you are forced to Auto resign.

Please advice.

What the hell are you saying?