Should Wall Street Help Enforce Gun Control?

The New York Times is floating an idea among financial services companies on how financial firms can play a greater role in tightening gun control, after the Florida school shootings last week. Conceivably, credit card firms could ban retailers who sell assault weapons, for example. Or, ban loans to the NRA, as one bank has already done. (PayPal and Square already ban gun sales on their payment platforms.) Need financial experts and gun enthusiasts to quote, pro or con, whether this is a good idea or not. Should finance firms take a moral stand? Or, should they stick with the status quo and do business with gun sellers and the NRA? Very quick turnaround, but I could use some fast, expert help.