Zazen dd2 is only 3 her pants are often a bit soiled as she insists on wiping herself. We keep spares in her coat pocket/the bathroom. However as they both are responsible for putting their own clothes in the laundry basket I haven't noticed any that were more dirty than normal. I tend to to just grab them out of the basket and stick them in the washer. Inspecting underwear is not something I do regularly.
Like I said the bin is not used for rubbish and hence not emptied. They don't play in their room. They annoy me by dragging half of the toy cuboard downstairs and cluttering up the living room and/or inviting half the neighbourhood to come and play on our PC (which is in the dining room) They are allowed to play upstairs, they just don't.
The lid of the bin was still firmly shut with it's little metal closer thingies. It never occured to me that they might be using it as a toilet.
Dd1 still denies all knowledge, but has admitted to being responsible for shoving washing under the bed because she cannot be bothered to walk the ten steps to the laundry basket.
I last gutted the whole room when they had a sleep-over about two weeks ago and the bin was fine then. Otherwise I just go in and gve it a quick sweep and dust when it needs it. I don't pay much attention to the bin.
As for neglected. They are rarely supervised when they are in their own home, unless they are cooking or playing with sharp objects. I don't see the need to hover over them constantly. They are both clean/fed/dressed appropriately etc. If not interfering with their play constantly is neglectful then I guess I am guilty of that, thank god.