"Gym etiquette question"

#PokemonGO: Hi everyone! So I'm fairly new to gym battling (in relation to a lot of y'all, at least) and I've run into a situation that I'm not sure is normal or not. I'm hoping y'all can help me out. So recently my S.O and I have been battling and putting pokemon in nearby gyms (per the norm) and we noticed there has been one player that, when we knock his pokemon out of a gym, will immediately drive out to where we are and knock out our pokemon out and fill up the gym again. (We actually think this player has 6 accounts as the gym will fill up with 6 pokemon from the same 6 accounts). When we try to battle it back, the player will continue to feed his pokemon berries until we leave. This player has even followed us in his car, knocking out any gyms we fill along the way. Is this normal? The following-us part honestly kinda freaked me out. Any feedback would be great! Thanks! via /r/pokemongo https://ift.tt/34bMUaQ