Today I went to Subway for the first time after the Apple Pay launch. Just took my phone because it's an official first-wave Apple partner for APay. No other customers in the store (dead time of day). So when I got near the register to pay and I didn't see anything looking vaguely like an NFC reader I though, oh-oh, out to car to get wallet.
I asked the employee if the store took Apple Pay. She said "No". She said that she could push a button and some phones could work. i see a QR box appear on the old-fashioned-looking car reader screen. Noooo, I don't think that's going to work for me. I ran out to car and got wallet. Still no other customers else I wouldn't be holding up the line like this. This time she totals it up and I see the NFC symbol instead of the icky QR code. I ask if it's ok if I run out to the car to get my phone again. Still no customers. She says, "ok". I bring in Phone and put finger on my Touch ID.
Cashier says to other worker: "That's the weirdest thing I've seen in a long time". I say, "You mean me running out to the car and back a few times {grin}"? She said, "No, the way you just held your phone up and the receipt came out on my register."
So, what I've been finding is that sometimes I have to persist to see how a particular store chain does the Apple Pay. I only experiment when no one is in the line behind me.
Macy's has been the only store that has asked me to sign after I use Apple Pay.
It's been sort of entertaining testing at various stores to find out who's in and who's not.