I love that people still say things like this. Game purchases are tied to your NNID, However the ID is tied to the hardware.
The tools to move an account to other hardware exist, and Nintendo will do it with absolutely no trouble if you call their support. It's incredibly stupid that they won't surface this to customers, but the infrastructure is there and is all rather easy to pull off. Unless you have a phobia of phone calls, it's trivial.
It's still silly that it's that restrictive. Anyway, I do believe people have lost their games because they couldn't prove their 3DS was stolen or other random accident that made them 3DSless. Don't quote me on that, I could be wrong, but I seem to remember something about that.
Either way, digital bugs me. I won't condone piracy, but I don't blame someone who avoids DRMed digital distribution.