Wouldn't it be abusing of the trust system, if you just give everyone negative trust who receives a significant amount of Merit from another user for a non-quality post? So if you want to give someone negative trust (and you don't care about your own) you just have to give him some Merit for a shitpost and he will be flagged even if he doesn't even know you and he had not the intention to abuse the merit system? 
Why will you do this from you main account ? It will result in your main account also getting negative trust and will make the account useless. In case, any one tries to play little smarter by creating a new account for this, he will have to wait for months before getting those merit points in bulk.
Also, if you feel that something like this has happened to you by mistake or other other account is trying to get you some negative trust, you can always appeal the case. A lot of things will be considered before giving that negative trust.