There hasn't been anything reported recently, so I haven't seen it. But if that is what is happening, if it upsets the seller, they SHOULD report it.
I think some people see it as free bumps, so they don't care..
I guess that's what it comes down to, does it upset the seller? It seems like most sellers these days just accept it as how its done today. Some encourage it.
I do my best not to get into banter in anyone's sales thread. I just don't think it's the place for it. Others obviously feel differently.