I know you may not want to go this far but would blocking the member stop it? I guess I should consider my self lucky just had 3 this am.
Had a similar problem on a different forum ( not the one most here would think) I had a friend/member every time he came on he would hit like to every post you did since he was on last about a week ago. He must of gotten tired of it I guess as he now only does it once in a while.