At a local high school football game the snack bar had an option to pay with Apple Pay. I chose that option and scanned a QR code on my phone and was taken to a site where I then put in the total for my transaction and could check out. The total was $5.
Later I was emailed a receipt and found out that my $5 charge was actually $6.46. There was a processing fee for $0.46 and a "Tip for Givebutter" for $1.00.
Givebutter helpfully explains they have 100% transparency with tips and fees. I think this is a big stretch when the so-called "tip" is something that is automatically added unless you are able to find the way to opt-out of paying it when you are checking out.