Your impression doesn’t match my reality. The Hell’s Mensans are behind these RG’s I’ve mentioned. It’s also a compilation of some of the more unpleasant stereotypes about geeks. First, let me give you a link to the Hell’s M Yahoo! group. I assume you’ve seen the website (the leather pocket protector is what we call a “joke” intended to play off the stereotype). The members range in age from early 20’s, I’d guess to over 70, and builds from downright skinny to vastly overweight. In short, we’re talking about a group of human beings.
The Hell’s M’s are the ones who’ll work out how to provide meals for a weekend for 100 to 200 people using such cooking facilities as can be set up in ordinary hotel rooms, both guest rooms and conference rooms, and do so without making the RG too expensive (the ones I go to cost between $40 and $70 for a weekend with meals and food available from Friday night until midday Sunday (midday Monday for 3-day weekends). The food, by the way, is good and plenteous.
That’s not the reason I joined, though. When I first started going to RGs, a friend and Hell’s M explained one of their purposes like this. The goal of the Hell’s M’s is to make sure everyone associated with an RG has a good time. This includes not only the people who are attending the RG, but the hotel staff (we usually feed some of them, too), the other guests in the hotel, and the police and fire department who are to have a good time by not being needed. Their attitude toward the odd jerk is similar to the SDMB’s, although I don’t know if we actually ban people. The Party Animal award at an RG is given by polling the members at the RG and asking “Who made you smile this weekend?” They are, in short, warm, funny, compassionate, and even wise people. Many of them are also my friends.
I went to my first RG not expecting to have a good time and expecting to run into the kind of arrogant, obnoxiousness others have described. Instead I found a group of people who are, in the words of Ed Zotti, some "of the smartest, hippest people on the planet, plus a few total dipsticks. " Sound familiar?
By the way, I’ve put Mensa on my resume exactly once, and that is a simple note that I was Program Chair for an RG while I was laid off. It’s under a section containing a bunch of miscellaneous awards, activities, etc. I wouldn’t dream of just putting Mensa membership on my resume and, if I were screening resumes, membership wouldn’t make that much of an impression on me except to double check to see if I knew that person. You see, in addition to the smart, funny, practical people I know who are in Mensa, I also know a bunch of smart, funny, practical people who aren’t. I also know total dipsticks in both categories.
In my experience, Mensa has been a lot like the SDMB with the addition of hugs and chocolate. If you look at my membership and post count, it’s obvious that in my book, this is a good thing! 
CJ
(By the way, I’ve never seen anyone wearing a leather pocket protector or, for that matter, any other kind of pocket protector at an RG. If I did, after I got done shuddering, I’d laugh at the joke. On the other hand, maybe I ought to get one for the next Dopefest.)