Oh my goodness, I just came on here to post about the exact same thing!!
DS is 3.1 and we started potty training him about a month ago. He's doing ok, still having an accident every other day or so, or maybe 2 accidents in 3 days on average but not doing too bad.
He's generally pretty good at nursery too, but I think they have this same sort of policy where they just wander off to the toilet and sort themselves out. So then he comes home and he still has poo on his bum.
I mean to be honest, I have no ideas how old he should be to start wiping his bum but as he's only been trained for such a short time, that was way down my list of priorities so although he wipes his own willy, I always wipe his bum for a poo. I guess I should start getting him to have a go, but I would be amazed (?) if many children could successfully wipe their own bottoms at 3?
Maybe I'm way off the mark there and it is just DS is behind the curve (I know he was relatively late training, so it's not incomprehensible that other children are better at bottom wiping than him!)
But I didn't want to say anything at nursery until I'd sort of got an idea as to what was 'normal'. I would have just thought that they would keep a bit more of an eye on them in terms of both bottom wiping and presumably hand washing. I mean DS does wash his own hands but it's a bit hit and miss. Sometimes great, sometimes pretty much just seems to wipe the soap all over the towel so just needs a bit of a reminder as to the general principles involved!
Does anyone know what the 'normal' age to expect to wipe your own bottom would be?