Not just gang tatoos. Here in the midwest, at least, jailbirds just love to get the crude india ink tatoos, especially on their hands, knuckles and forearms. These are not the colorful tatoos you are used to seeing but the crude, faded, blue tatoos. They are often just initials or a cross or something. Any employer knows that tatoos like this are a sure sign that the person you are dealing with has done some time.
Its fine, but some folks may not understand or get it, and think its a gang tatoo.
I've seen some of the jail tatoos, they are easily recognisable, and most of them are also repetitive.
One funny story involved a guy I know who is a tatoo artist and was doing tatoo work on a guy, the customer had erred in the spelling of someones name, so it came.....well, not to good.
lol.