Many years ago I stumbled across a grunge Japanese band out of NYC where, at least, the vocal singer wears diapers in everyone of their concerts.
They are called Gelatine5 Here's a couple of their musical videos found on youtube:
YouTube - GELATINE - New Monster
YouTube - CHANNEL ZERO #8 Gelatine Live @ Crash Mansion Pt 1
So does anyone come across a band that you've seen worn diapers before?