I have the same issue. I don't use any mods or cheats when and yet i still got my rep down to 60 and it seems to decrease every time i play something. The worst part is i don't even know who reported me or why they did it. It seems people can just report whoever they want for no reason and get away with it.
I realize this is a beta, i hope this issue is resolved so that we don't have to worry about this kind of stuff when the system is fully released