I think some of it depends on how the person with the art feels about it. I am not a big fan of tattoos. If I met a man who was covered in them it would probably be a dealbreaker. If I met a man who had one and felt that was enough, ir would not be a deal breaker. If I met somebody who was planning mutiple tattoos in the future I would probably see that as a deal breaker.
I've been very interested in this thread because of my situation. I have extensive tattooing - over 25 hours worth - but it's all on my back and upper thighs. I mean, this is not just a tattoo, but it significantly and drastically alters the look of my body. I also dress fairly conservatively, with minimal make-up, business casual clothes, little to no jewelry. I do not look alternative at all. It would be very easy for someone with conservative tastes, who may not prefer tattoos, to see me as someone who would be unmodified.
So I actually do proactively tell (theoretical) potential partners that I am extensively tattooed. It is not something one would expect from seeing me, and my tattoos are strategically placed so that they can be covered by my clothing, since I am in a somewhat conservative academic field. A potential partner could easily have no idea that I am tattooed until we are intimate, and I don't want someone to find out about such a major aspect of my appearance at the crucial moment, if you KWIW.
I think the onus is usually on the person who doesn't like tattoos or body modifications to say something, but I also think that if someone is extensively tattooed and it's not obvious, it's smart of them to speak up and casually let the other person know. One small tattoo is one thing, an enormous piece is another.