How do they know that?

I'll bite. In this game it was my turn to be psychic: http://drawception.com/viewgame/rrnTwmHCha/this-is-a-test/ I guess mediocre just means C minus to me...

coincidence maybe?

People skipping a lot of games sometimes tend to see different stages of a game as they go along :)

2 & 10 in this one are very similar. http://drawception.com/viewgame/dgfMst87mZ/the-gruesome-cereal-killer/

I have to say, I was pretty happy with myself on this one: http://drawception.com/viewgame/gDa4fQrNqk/dr-tran/

But as I explained in the comments, I figured it was him since he always does those damn laser eyes.

I go with wkommor's conjecture. Though it's something that wouldn't have occurred to me, given that at least early on I tended to accept whatever came my way, so I didn't tend to see much of the games already in progress.

Of course it could also just be coincidence, but I've seen other examples that seem to fit better with what wkommor suggests, that a lot of regular users, especially those more picky about the cues they'll accept, will tend to get context clues sometimes without total confirmation.

Melissa points out another aspect I'm just starting to realize, that those who are here long enough tend to recognize some of the habits of others, especially patterns that serve as any kind of signature.

This might sound weird but I have skipped over prompts before then later gotten the picture that somebody drew for the prompt i skipped earlier. That or i get a later panel in a game where i had skipped a pervious prompt. I feel like this could happen sometimes, even if it is just subconscious for some people.

LK one time I got one of your drawings and I knew it was your style so I said "LKICU" at the end and obviously it got dustcatchered but I was like "That will be so funny if it doesn't"

"combo breaker".

Not sure if it needs linking, lol