I've got one UPS store that insists on every package being scanned, easily a hundred a day. Others don't care.
Zales, Kay, certain electronics stores and warehouses, and a lot of the small businesses I pickup from all insist the driver scans every package. They won't let you leave with them unless you scan them first.
Sure, if you're scanning 200 surepost bags from a clothing retailer, it could be argued you're stealing time, but there isn't one uniform rule across the board about scanning p/u pieces here.