[TylerE]

Is there anything stopping you from getting a card for 555-867-5309?

They need a phone number. I've never heard of any store actually trying to use it to contact you.

PS: If you ask nicely the cashier will almost always punch in a working number for you. They want the reward points.

[kamarg]

Not at most places and often times that number will have a large reward points pool already built up because others are also using it to avoid giving out their number.