Never encountered any of these while caching, but I know I have found a few that were questionable at rating. All the 4+/4+ caches I have found were quite challenging.
The closest to "liars" I have encountered were 1-2 level rated caches that were actually much harder... but I guess that is still in the level of those go to find them.
Personally, I think ratings should be as accurate as possible. A "5/5" cache that is not really a "5/5" or at minimum equal to a "3/3" is grounds for reporting to a reviewer because there is no reason for making fake "5/5" caches just to get tough cache.
I mean, I have actually found a 5/5 in the middle of a park in the middle of a city. It required ropes and rigging to get it. I have also attempted other 5/5 that required going into drain tunnels and other sketchy locations... There are always urban locations for a 5/5 so calling a lamppost that just for the sake of getting a hard cache kind-of defeats the purpose in my opinion.