On the rules in the multiplayer categories it says that I "can play with other people", does this mean that I can choose to not play with more people?

The rules have been updated and it stated that in the "Multiplayer Category", you are forbidden to play alone and needs a minimum of 2 player in order for the run to be verified. It is also allowed to have more than 2 players for the run.

But how can you know they're random people?

@ReverseVideo if you see the rules for Multiplayer Cheese, it is said Minimum of 2 players, you can add more than 2 players. For example 3 players, however, those 3 players need to get cheese and enter the mouse hole.. if one dies then the run is over.