Paint can be removed.
Best to start with weaker solvents. "Goof Off" would be a good starting point. If that won't touch it I would try lacquer thinner, using it sparingly and quickly (meaning apply it in amounts that won't run off and wipe it back off immediately). Last resort would be acetone.
Use a white cloth/paper towel (unless the vehicle is white) so you can see if you are removing paint. If the cloth shows color but the vehicle doesn't seem to be losing paint then that is about perfect. That way you can go at it in a controlled fashion and not remove the printing on the tag before you realize you have reached the tag.