I voted yes.
As long as I'm home alone, there's no point in wearing anything but my diaper (and a t-shirt, if it's not summer). However, as soon as I wear normal pants with my diapers, either at home or out in public, I put on a pair of underwear (boxer-briefs). They keep the diaper in place in case it starts sagging, and they also significantly reduce noise, and the last thing you want when going out in public is being discovered.
Besides, when I go out in public, I rarely take a new diaper with me. So if I have to change out of the diaper for whatever reason before returning home, I can just remove the diaper and have my proper underwear on me already and I'll be properly dressed (and all guys know how disturbing it is to have your parts rub on the rather rough surface on your pants!).
Peachy