Heliduck, in my experience there is a third type of person who wears tattoos: One who has numerous, expansive ones, but keeps them under wraps because he knows they are socially unacceptable. Trust me, the complex psychological issues such people have are troubling to people like me. Please don't even try to tell me you got that huge, hideous tattoo on the back of your shoulder because you like looking at it. Oh? In the mirror? Because that's the only way you could possibly see it. Or...is it that such a person wants only *some* people to see their tattoos...just not their Chief Pilot, perhaps? Why not? Ohhhh, because big tattoos tell the world, "He's a rebel!" And rebels (with or without causes) might make great subjects for cheesy movies, but they make lousy helicopter pilots.
I have a young pilot friend; I knew he had two small tattoos (one on each arm) but didn't know the half of it- literally - until we went to the beach recently and I saw him in a bathing suit. And I saw the other big tattoos on his body as well as the starburst around his navel. I was, like, WTF? And I've known this guy for a couple/three years. And you know what? It colors my opinion of him now. I understand why he has an anti-authority streak a *MILE* wide. Or maybe I don't understand it - maybe it merely explains it. I predict for this young pilot a long career in the utility field, as he will never make it in mainstream aviation. And not because of his tats, but they are a good "pointer" of his other issues.
As for your scenario of a pilot who keeps his tattoos hidden for "years," yeah I'd probably still find a way to get rid of him (he says with a "that's life" shrug). But I have feeling that this would not happen. I suspect that such a pilot would probably exhibit anti-authority, anti-social, or other such undesireable tendencies that would make me want to get rid of him long before that. Are you the exception to that rule? Good for you.
Having said all that, let me repeat: I personally don't like tattoos. I understand the single, meaningful tattoo that many people get on the forearm or wherever. I do not like the multiple, big, colorful, expansive ones- the ones that become body art. While they are (sometimes) interesting to look at, what they say about the owner's psyche is disturbing. I wouldn't want such a person as a pilot of mine. Simple as that. But my generation is dying off. Maybe our successors won't be so antediluvian and didactic and narrow-minded. In the meantime...
Bottom line: aviation is not currently tattoo-friendly. Display them at your own risk. Heyyyy, didn't SASless say that very thing, what, 20 posts ago?