Tattoo Etiquette

Almost seems like an oxymoron.
Tattoo conjures up something counter culture, grunge, possibly subversive while etiquette conotes its spectrum opposite: refined, elitist, priviledged. But there is such a thing as good form even when engaging in conversation about indelible body marking.
How many times have you over-heard this exchange:

"You have a tattoo?"
"Yeah"
"Yeah? Where?"

The fact that a tattoo is not visible should tell the inquirer that there is good reason this is so. It's much like an expensive boutique that does not display prices, in which any question about the cost of any item is quite simply out of place (a rule of etiquette). And so it is with tattoos. Why it is that the curiousity minded questioner must fill the dead air following confirmation of its existence and ask about specific location is merely evidence that a basic rule of etiquette is not being observed. But then the tattos artifact is one with a host of prejeudice and judgment attached to it, so this perhaps is less than surprising.
Why not allow the owner a modicum of respect, and allow her or him to volunteer this information instead? Perhaps somethings are left better to the imagination anyhow.