If you see someone beating a golem, always! But don't report the old school ones training on NPC fighters and paladins!
IMHO, I don't think there's anything wrong with using a Golem. I've used a golem before to train combat skills quickly, because combat skill training can be tedious.
My way of looking at it, is if they don't reply when you ask them a question such as,
"What colour is my body sash?" Or if they answer with an automated response such as 'Yes' or 'Hi', then that's when I'd page a Gm..
If they're just bashin' a Golem whilst at the keyboard, I think that's perfectly fine.
(reason why asking them a question is good is 'cause loads of BOTS have an automated response when text enters the screen.)