How can one terminate a drawn game ie: 3 move repetition, 50 move rule etc., when one's opponent does not accept a draw offer in these circumstances?

agmac,

That functionality is yet to be added to the system. Send me details of the game and I'll see what can be done.

Regards

Game 38056. Although Kyntanylha is a pawn up, the game is an easy draw even without the fact that the position has been repeated more than 3 times. Kyntanylha seems to be quite a strong player, so I'm sure he realises that he can't win from this position.
Regards.....Andy.

justified, but on occasion I'll play on in positions without much in them, looking for a frustration error.

Since the functionality isn't in the software to adjudicate draws according to the rules of chess, IMHO that responsibility would fall to Stoney X, to adjudicate manually.  I suspect it's a rare thing when someone wants to continue after a three fold repetition of position, so not a big additional workload for Stoney.