The bartender has a tablet with faces of everyone nearby he can tap. A lot of the service on Regal still asked your stateroom to verify they have the right person or whatever reason. Some service didn't ask my stateroom so they either remembered me or saw my face on their tablet.
I ordered a water once sitting around a busy bar and the service person gave it to a different person that kind of looked like me. I had the drink package so I just got another one.
A couple times in the casino I ordered from my phone sitting at a game and they came and found me, but other times struggled and I noticed a server walking around looking for me, so it is not super accurate for them, specially in a busy area. I did like ordering drinks to my room from the phone app. That was handy, like when I wanted a water before bed.