Same here. I'm sure it's been well documented, but I quit doing the coins last summer because of the hassle.
Trip #1 - "oh wow, how cool!"
Trip #2 - "You're back again?"
Trip #3 - bank tellers and managers crowd around and ask questions (albeit curiously/semi interested)
after awhile, it got to be too much of a hassle for the ~1k-2k airline miles per trip. Anything more than that and the hassle would have been threefold.