How likely is a game with 0 inaccuracies to be played by a U2000 human?

#1 When I'm playing a game, 0 inaccuracies is unlikely:

"How likely is it to play a game with 0 inaccuracies?"

I guess a proper multivariate analysis would find about four main factors:
- number of moves in the game
- playing strength
- opening
- time control

So if you play a tactical opening in bullet as a 800 rated player and finish a 140 move game getting 0 inaccuracies would be rather suspicious compared to a 2700 rated player accepting a draw offer after 12 moves.

That being said, if you are certain your opponent cheated, report him and don't use the forum. Imo one game alone usually is not sufficient to assess cheating with some exceptions, and inhumanly equal move times can be more of an indicator than random "perfect" moves.