My pants and jacket have zippers across the back that I do use to attach them together. That keeps the jacket from riding up. Though I've never noticed it riding up when I forget to zip them together or if I wear the jacket with regular jeans.
'09 R12GS, '05 GSX-R1000
Iron Butt # 4999, WERA/CCS EX # 666 (currently, expired), AMA Life Member
Racer, Drummer, Bassist, Software Engineer