Did anyone expect anything less?
Pay your employees the same wage as an immigrant field worker and suddenly you are surprised that they take liberties with customer data? Yeah. Brilliant.
Truth is, this should not be going on, but Best Buy (and the other chains, I'm sure) do little to prevent it. Bottom line, they should be doing continuous scans to check up on their staff. Some $4/hr class D techie isn't going to police himself. To think so is to practically endorse such behaviour.
Make the policies, stick to the policies, enforce the policies. This is a classic example of a company creating a policy and then not enacting any means to enforce it. Then, when it is seems to have gone astray (publicly), the crackdown comes in the form of a random round of firings.
Personally, if I was fired by Best Buy, I'd sue their assess off.