How do you know they were cheating?
How do you know there isn't any anti cheat?
I know for a fact that if the server doesn't think your position is a fair position it moves you to your boat. Sometimes you get stuck in a glitchy spot or if you are inside the hull of an enemy ship while it sinks you can force the server to teleport you for "cheating."
I don't see a huge cheating problem in SoT either. I imagine there are some out there doing it, however, the developers seem to be doing an okay job of keeping them at bay. Any one played Counter-strike 1.6? Talk about a cheating problem. I'd say that in general SoT is on the right track as far as cheating goes.