I have no problem with businesses that require cash payments (except for the inconvenience to me) but I recently found out that a small business I work regularly with asks for cash to avoid taxes.
Now there’s several legitimate reasons a business might require cash. One of our favorite restaurants only accepted cash. People living day to day on odd jobs or paying daily contractors might find cash more convenient. I wouldn’t normally question why they wanted cash other than random curiosity. Would I worry that they weren’t paying their taxes? No, I’d consider that their responsibility, not mine.
But now that this business wants cash to avoid taxes? Now I pay with a check.
Is it my job to enforce US tax law? Nope. (Or at least I don’t think so.) Is it my moral obligation to not enable a crime? Yes. Am I being a too goody-goody? I feel like I might be perceived that way. Especially since in the eyes of many taxes are necessary evil and would think not paying taxes is a less evil crime than stealing from a neighbor even if they were for the same amount. If I really want to do the right thing, I should probably stop doing business with them.
I feel it’s not fair to society that some don’t pay taxes. They use the public roads and schools and need to contribute like everyone else. (I do believe there should be exceptions for those that don’t make enough money to survive comfortably. But that should be worked out fairly across society.)
It reminds me of all the social experiments on cooperation. People are willing to take a personal hit (like pay money) in order to punish people who don’t cooperate. I don’t have a link for the studies but see the Tit for Tat strategy in Prisoner’s Dilemna experiments for an idea of what I mean.