I've "heard" that it's a nice thing to do to bring a box of chocolates or something like that to "thank" the entire flight crew (something they all can share), but the thought that this is a "tipped" position seems to feed into the "trolley dolly" moniker they have worked so hard to overcome. ("They" being the flight attendant community). They are primarily there for safety, and it seems wrong to "tip" "safety personnel". We don't "tip" police, guards or firefighters do we?
This has to current effect on me, though....because I will not fly ANY of the low cost carriers. No way am I going to trust my safety and comfort to those airlines. Flight attendants for regional carriers and the low cost carriers are pathetically paid. So, I can understand why they might want to accept tips. My BFF's daughter worked for a regional carrier for awhile as a flight attendant, and she made less than $20K per year....for a LOT of hours. But they are only compensated for hours AFTER the plane leaves the gate and before it returns to the gate. All the pre-flight time is uncompensated. Seems very wrong.