I have been carrying IWB FR for years now. I do have a bit of concern if I get stopped (the law here says Furtively carries with intent to conceal any dagger, dirk, pistol, or other dangerous weapon . . . is guilty of a gross misdemeanor.)
I am a bit concerned that if stopped any cop can say that I was furtively carrying with intent to conceal.
I don't think that this would be an issue if I wore the same knife clipped in my pocket with the clip showing.
That said, I am what some people would term "festively plump" and I find that iwb rf is very comfortable to me. (every once in a while when I don't have the knife perfectly positioned, I will get an uncomfortable poke.
One real plus with this method of carry is that I never hook the clip on anything, or scratch furniture with it. One reason I switched to this method was that being a larger guy I ofter scratch things with the clip on my pocket. I hooked the clip on my favorite carry knife badly a while back an now the clip is not as tight (I don't have the tool to take it off and bend it back). as such, the knife is much more prone to slide out of my pocket now.