RST Engineering wrote:
Because...

(a) it costs me 4% or so to ACCEPT a credit card and another 4% to issue a
credit, I'm out 8% of the deal from the getgo

Hotels do something similar -- it's not actually a charge, but they
sort-of claim some of your limit as collatoral or something like that.
Or maybe they just keep the credit card number around just-in-case.
There may be different fees that are no less prohibitive, though.

-Luke