Every time I check out at Kroger (or similar membership-based store) I tell the cashier that I don't want a membership but I do want the listed sale price. They always just scan their own card.
CVS started to refuse to scan the 'house' card as of about a year ago. and they try to collect your phone number when they hand you a card for the first time.
Every time the item has a digital coupon advertised price I simply inform the cashier I don't a phone with me. They discount it immediately.
I've had this work occasionally but often the opposite experience unfortunately.