Single post in Moderator applications

Ah, I guess if we're allowed to ask questions... Is it expected of every mod to be able to come to a decision on more grey-area issues/reports? (For example, determining whether something is vaguing/disrespectful to other users, as it is often up to interpretation more than, let's say, double posting) Or would it be alright to be more of a "spotter" and bring attention to questionable behavior even if just by yourself you aren't sure what decision to make? (While still taking care of the more concrete rule-breaking/other duties)