Although all fluffies have a sense that poopies need to go some place domestics tend to retain the desire to make good poopies in the litter box as it has been reinforced in their minds through litter training. Runaways often have issues with figuring out how to relieve themselves without a litterbox. This can lead to UTIs and constipation.
Some runaways take too well to the freedom and won’t even clean themselves, this too can lead to complications.