>>87230 (OP)
I don't know what products are actually out there, but I have fantasized about those kind of pads quite a few times.
Just imagine an older loli who wears pantyliners/guards every day because she doesn't like using the toilet at school. They're not absorbent enough to hold a full wetting, but she doesn't have to worry so much about little leaks while she's trying to hold it. Basically she spends the whole day with a full bladder, squirming and slowly dribbling into her pad. Sometimes she might go into a toilet cubicle to change her pad if it gets too soaked, but she still doesn't use the toilet. Other times she might forget to change her pad and end up leaking into her panties.
As for diaper swapping, I quite like the idea of a loli being changed into her baby sister's wet diapers as a punishment or just to save money.