Angelina but of course it would have to be a onesie that you can take off.
Yes, I was thinking about a normal onesie that is not hard to take off. So it would only be a very gentle deterrent; a bit like being your own keyholder: just an extra step to take (opening the zipper at least, but perhaps needing to take it off fully to be able to fight 'effectively') that might be enough to stop you from trying.
But I wonder if people who wear thighbands at night, don't mind being clothed at night, and do not have to go to the bathroom during the night, would prefer to wear a onesie that they could not take off themselves, if that would mean that they wouldn't have to wear the thighbands then.