In the end of the day the best way to contribute to change is to not conform to the shit that you don't like. Vote with your wallet - literally.

Credit card surcharges are pretty cheap - and it's actually illegal now to charge more than the real costs.

So if you wanna buy a $4 coffee, if they wanna add surcharge, of say, 10 cents (which is over 2%, so even that is a bit high), then by all means, I'll cop that.

But to flat out refuse any transaction under $10 pretty much means they're just wanting to build up their pool of cash transactions that can go undeclared and therefore they save money on their tax bill. That can be the only explanation.