Is he cheating?

http://de.lichess.org/analyse/mvzi68sl/black
http://de.lichess.org/analyse/jkdi9sxy

Perfect play for Sjurd ...

Apparently this http://en.lichess.org/analyse/jmmao0rz/black is a game where he doesn't cheat. Anyways, report him if you like and let a more experienced moderator figure it out.

I suggest not. First, the play wasn't, in fact, perfect, even when assessed with the very high hurdles for errors used in the analysis.

Second, there's a good mix of thinking times.

I think he's just damn good!

I th

He is already marked. Thanks for that.

Wrong again!

Again? Can you explain?

All my opinions today have been disproven.

Is it possible to prove an opinion?

One can look at the probability of it being right. Probability and 100% proof are two different things. (Also, 100% proof is undrinkable.)