Let me first say,I do not believe ANYONE on the boards is getting any preferential treatment in regards to siggies, avvies and the like.
Having said that, it's not uncommon on boards such as this for those who are significant contributors, either financially or informatively, to get recognised with enhanced features.
The CM staff are all VOLUNTEERS, they give countless of their time building and testing maps, researching and planning gameplay options to bring us first class realistic scenarios to participate in. As far as I'm concerned they can have 1Mb avvies and 50 line siggies.