The mods are human, so they will make mistakes.
However, watching all the different mods over the years tells me a few things:
1) Favoritism isn't there...but there is "reverse favoritism". What do I mean? People who get a reputation for "bad posting", trolling, hating, negativity...if their names come up in a report its more likely action will be taken. Everyone else is treated relatively the same (I've had many, many posts moderated and deleted for various reasons, mostly because another [who I quoted or was replying to] was moderated. Yes, sometimes my posts needed to be moderated, I'm human too) regardless of title, and for those who think otherwise, MVPs will get moderated even more strictly than regular posters since they have to follow higher standards than us.
2) While there isn't favoritism in posting, there is in reports. Why? Because some posters actually use the report system correctly, and when they submit a report it is almost always something that needs to be moderated. There are others whose reports get pushed aside for later, as they abuse the report system or like to submit a lot of very low-poriority reports (pretty mych judgement-call type moderation reports that may or may not need moderation)
3) Reports themselves. If someone has a lot of reports on them (their posts keep getting reported) they may get a warning even if they don't think they're breaking any rules. Sometimes people do take offense at your posts and report them, or if you're doing light trolling that is within forum rules but people notice it and report it. Get too many reports on you (especially on a couple posts) and you can get warned. The mods are generally good about ignoring report spam abuse on someone, but new mods sometimes slip up. Get enough flags and you can get banned.
4) Posting habits are very important. If you keep making multiple threads on the same subject or complain about how the forums are run, or do some light trolling or such, you're going to get targeted by the mods; maybe you won't get warned immediately, but when you do something within forum rules that requires the mods to look at your posting history (like submit a report on mods) you can get a small ban for your past actions. They do keep tabs on how people post, and if one notices a lot of notes on someone they can get a small ban.
5) PMs are very good for getting an answer from the mods; complaining on the forums or asking for an explaination on the forums is not (and I think is against the rules).