Well i have noticed this.
Mods, Experts and Editors tend to be more knowledgable than normal users so they are a more reliable source.
Mods/Experts/Editors make friends quicker because they are respected users therefore normal users upvote their answers to earn there respect.
This may just be that their answer was a really good well thought through answer
Because lots of users are friends with mods/experts/editors there are more people to upvote if it is a good answer
This is what i think to this issue.