We're a lot more worried - because we're hearing a lot more chatter upstream from the Citi's of the world - with Visa, MasterCard and Amex all talking about the logistics of refusing the transactions associated with ARs. They've already generally decided the optics of it are okay.
Basically, they're looking at it and saying, "if Congress is unwilling to act, we are going to use our clout to do something about it."
There would of course be a ton of lawsuits - but it takes a bunch of money to litigate - especially against groups that have as much money as the card networks have.
The pragmatic reality of the matter is that places like Palmetto State Armory and Primary Arms - and even higher end boutique shops like Daniel Defense, Larue, Noveske, etc. are dead in the water in about 45 days if sales go away.
Yes, there will be groups that try to bring alternative payments to the front - but if the cannabis industry offers any lesson - that's a hard problem for a variety of reasons - and you've got to have banks willing to deposit your money at the end of the day.
Were I ranking threats to the second amendment, right now I rank Congressional Republicans number one, active state legislatures number two, and this would be a close third.