To me, it depends upon where the FA's are in their service. If they are still doing stuff, then I will wait until one passes and get their attention, using the "when you get time" line.

If the various "services" are done, I may press the button - or I may get up and stretch the legs...it all depends on if a toilet visit is required.

Sometimes however, being an aisle seater, if one of my seatmates need to get up then I will too.....

It all depends upon the situation - never had any reservations about doing it though!