One of my buddy's actually had them refuse to sell him some parts. He had given them his address and all (not a confrontational person) and they denied the sale. I bought the stuff for him. I used cash and did not identify myself. I get the feeling Radio Shack had some other stuff going on.

They would sell that information to skip tracers. CVS was big into this as well.

These private parking things are similar, there is a network of near real-time alerting about vehicle location for repo men.

For stores with return policies, there is value in knowing who may be abusing them and/or causing them to lose money.

He never returned anything and was a pretty frequent buyer (he was big into a lot of hobbies that he could build electronics and he built stuff for work). They rung him up and then the store employee said they couldn't sell him these items. He started ordering from catalogs after that. Didn't matter much I guess as Radio Shack stopped selling components not long after.

When I worked at radio shack we would send catalogues, later fliers.

We would ask during a return and require it. When buying anything with cash it was optional. The sales staff had to maintain an 80% ratio per day.