To the OP: my experience is the flight attendants (FA) will not know you are on a miles ticket. A long while back someone on here explained something about various records that the ISM or head of the cabin had, including possibly what type of ticket you are on. I seem to recall that technically, the ISM could figure out that you were on a miles ticket. I don't actually know the details of that hopefully someone can clarify - it was quite a good explanation by someone who clearly had taken the time to understand how passenger details are communicated between travel agent, to check-in, to the plane.

But I am quite sure the FAs who service you are almost definitely not going to know you're on a miles ticket....they tend to only know know if you're a DM or not (the list of DMs is often posted in the back by the galley, written by the section leader), and then, in descending order depending on the diligence of the crew, they'll know if you're OW Emerald, CX Gold, Silver, etc. The average BC (entry-level FA), some of whom will be in J class, will have absolutely no idea you're on a miles ticket, and I really doubt the FP or SP would as well. They spend most of the time before the flight preparing the plane and hurriedly getting food ready, not scanning the passenger list for code indicating the type of payment the pax made. When personally flying on miles, I have never had anyone on the plane indicate to me they knew how I paid (miles, btw, are absolutely a form of payment...it is not a "free" ticket from the airline's perspective).

Lastly, the one thing all the FAs definitely DO know is if you're an op-up.