I would step in if anything was detrimental to his well being (ie outdated info ect) but in regards to what they do with him while he's in thier care I'm not particularly bothered. If he's happy then I'm happy.
The only things I've ever really had to mention were the drinks they were giving him, flavoured water which they assumed would be a good thing but in actual fact it contained aspartame. She used to give him water whilst being FF, another outdated thing. No big issues at all, I'm just very grateful for the small amount of sporadic child care i need so we've no need to use nurseries.