I love tattoos. If I truly had my way, I would have full sleeves. But, there is a reason I don't. It's the same reason I don't cut my hair in a 'non traditional' (buzz, mohawk, etc) manner.
For what this information is worth...meaning...don't be an idiot and use this info to avoid proper authorities....
Identifiers are used globally. They are international. They are interlingual. You cannot escape them...unless you plan for it. Identifiers are what is used to recognize you. Digitally. And physically. We are going to talk about the physical.
Let's say you are 5'9". Average build. Dirty blonde, average hair cut. All your teeth. No tattoos. No piercings. No need for reading glasses. Maybe some scruff, perhaps even a month old beard. No physical inabilities (limp, etc), no obvious scars, etc. You are pretty average. Hard to distinguish from others. Easy to blend it. AND you have options.
Shaving the beard. Getting some Just For Men for the hair (or beard). Styling your hair differently. Putting on some non prescription reading glasses. Walk with a 'swagger' or limp. A fake earring here or there. Fake tats here or there. You get the point. You have options. You are a blank canvas. The trick is to always be able to go back to that 'blank canvas'.
Think about your personal identifiers. Is it your walk? Your hair style? Tats? Glasses? What never changes about your physical appearance? Can you cover up tats? Sure. That's an option. But what it you have to take that shirt off? What if you have to jump into water? What if the tats are places your can't cover up? (hand, fingers, head, etc). Same goes for piercings. You can always take them out...but the hole is still there.
Looking for identifiers. There are the obvious ones (what we have talked about above). Now, for those of you who pursue individuals who are trying to hide... you've got to look beyond the exterior.
Lisps. Speech impediments, twitches, nervous ticks, smaller details. Preferable items (always ordering a specific kind of coffee/drink, etc.) Habits. Anger. Compassion. Things that are not so easily hidden. Things that are molded to the inner character that cannot be changed overnight.
We have teams of analysts working around the clock, year after year, tracking the bad guys of the world. Trust us, they aren't just looking for the obvious. A child can identify her mother or father in a crowd of people. An analyst must identify someone they've never met (most of the time) in a crowd of millions. And often from a desk. Think about that.
Think about your identifiers. Are they harmless? Do they make you a target? If you had too, could you change them?