The only access Wal-Mart has to gun trace data is from when the ATF runs a trace on a gun they sold.
They would be foolish not to keep track of requests for gun traces that the ATF makes of them. What they are doing in addition is flagging the customers that bought those weapons so they can determine if they want to continue to sell to them or not.
Then even if you pass the NICS check (no warrants against you or felonies), Wal-Mart can refuse to sell to you if the Bloomberg file thinks you may have bought a “crime gun”.
If you purchased a gun from them, and then the ATF runs a trace on it, they will flag your name. However, the ATF does sometimes run traces on guns that were not used in a crime, but are merely evidence.
I have no idea if Wal-Mart will refuse to sell guns to anyone who's previous gun purchase was traced. The article says they could refuse to sell to that person, not that they would refuse.
However, even if they do refuse to sell you a gun, you could just go and buy one from a different retailer.
I think it is a really bad idea for Wal-Mart to try and do the ATF's job and detect illegal gun trafficking. However, I also think that Wal-Mart should have the ability to refuse to sell to people that they have reason to mistrust. I however, don't think that having had a gun they previously purchased traced by the ATF by itself is reason to mistrust someone.
I think that every gun dealer, Wal-Mart included, should have the right to refuse a sale to anyone they mistrust for good reason. Say they appear to be a straw purchaser, or they don’t have valid ID, etc. I just don’t think a private retailer should make decisions of this nature based on Bloomberg’s criteria, since he doesn’t even know firearms law or that dealers are inspected by ATF or that buyers have to pass a NICS check. Bloomberg is an uninformed boob with a political agenda. Wal-Mart should not be subject to his schemes.