Expecting Rain

I'm just curious about what actually happens if a poster complains of abuse or hits that little red exclamation mark. To be more specific:

1. Is the complaint investigated at all before issuing a warning or banning someone? If so, how?

2. Is more than one moderator involved in the process? If not, are there any steps taken to avoid a situation where the moderator assigned is a personal friend of one party and thus might take a biased stance?

3. Are warnings/bans reversable if the complaint is found to be unsubstantiated?

I'd leave it alone. Something tells me a foot will appear and kick me right in the nuts