My daughter went to JK with me always double checking her bum after she wiped ~ which might have given her the lazy sorta wipe thinking ahhhh Mom will get it anyways. I ended up with her getting rashes on her bum as she woudn't wipe properly as her teacher wouldn't help her.
With my second daughter..she is going into JK this year and I"ve made sure that she can clean up herself ! I figure around 3 1/2 they should start wiping themselves and I do check but I get them to wipe, look at the paper for poo...and wipe again until no poo on the paper. We go through a lot of wipes (for training I use wipes ) but then I have a garbage pail just for dirty paper/wipes so my potty doesn't clog!!