I have come across only one or two such coins so far and it is a bit depressing and wrong. Just like it is wrong to mark up all over the obverse and reverse of halves so over time it looks like a mess of graffiti. I am not saying that an already beat up coin is disfigured by some marks, but what I see in my area is EVERY single coin has to get a mark, then another, and another, etc.
I guess the only good that can come from rim painting is if some of the CRHers who mark up their coins as described above wind up getting "punked" by finding the painted rims. In that case I think it is "just desserts".
Just my 2 cents.
Jim