I'd say the whole touch thing is cultural - I'm deaf, and as such, we can't exactly say "excuse me" to get someone else's attention, so we will touch to alert them to our presence. Deaf or hearing, it doesn't matter; it's just MUCH easier to tap someone on the shoulder. I have a quiet voice, and I remember recently my FH (who can hear) and I were at Universal Studios for Fright Nights. We were trying to make our way out of this incredibly crowded place, and since I was in front for a change, it was up to me to get through the crush. I stood directly behind this woman, yelling "Excuse me! Exucse me, please!" and she didn't budge. So finally I reached out and touched her lightly on her back, putting a little pressure on. She *finally* noticed me and moved, and at the same time I said "excuse me please" *yet* again.
Sorry for the slight off topic post.
As for tattoos, I have four. And I'm proud of every single one of 'em, and I have plans of getting more! My next one will be a visual imagery of my screen name - DragonYoga. I've had people reach up and touch the tattoos without asking, but that was rare. I do get asked frequently if my tats are real... Uhh yeah? *G*