Re: Is it possible to reverse a given merit sent mistakenly to a different post?
But if he was a newbie or something I would be worried like if he turns out to be scam, then I will probably get linked to him through that merit 
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No, nobody would make such a connection without any other proof. ...There was a thread created a few months ago that shows statistics of how many banned members each user has merited. On top of the list you can find many well know names including merit sources. https://bitcointalk.org/index.php?topic=5117555.0;all
My point is nobody can know if the person you merit is or will eventually become a scammer or banned.