Tino, not sure that's right. I suspect that at a Ticketmaster store location, even if you pay cash you can't get around the convenience fee. Thus, Ticketmaster is not surcharging for credit card usage. Now, is some other company effectively using Ticketmaster to surcharge. Probably not. For some events, you can only buy from Ticketmaster so we don't even have to worry about the other company. For those events where you can also buy from the other company, in most if not all cases they will accept credit cards for payment at the same price as for cash transactions. The convenience fee you pay Ticketmaster is really the price of their service as a ticket broker, like it or not.

I also note that Visa appears to be quite serious about not letting merchants (e.g., the IRS) circumvent their no surcharge rule, so no reason they'd let Ticketmaster do it.