What happens if you get any MRI? Does the tattoo heat up and burn you? Does it get pulled out of your skin?

Good question, I don't have any empirical evidence, but it makes sense that the tattoo would be pulled outward. It is still in the patent process, you may have found a real disadvantage. Not that the price of an MRI in the US isn't restrictive in itself.

But who knows?

Interestingly enough, half of all the MRIs performed are in the US, they are also much more expensive here. But back to Nokia's tattoo. So 60 million people out of almost 7 billion. The 7 billion stat is from 2009 and the MRI stat is from 2007, but close enough for speculation when no money is involved.

So the risk of a tattooed person, if all people were tattooed, is close to 1%? Of course, not all people are going to be tattooed, so that would drastically reduce the chance that a tattooed person would need an MRI. We need more statistics, because I also think the people who would be up for a vibrating tattoo are the sort who could pay for an MRI, so we would have to take that into account.

All and all, I think Nokia is willing to play the odds.

It's about the individuals playing the odds. Most of the people who would get something like this probably live in the developed world where MRIs are available. Getting one of these tattoos might exclude you from having a needed diagnostic procedure at some point in the future.