I am an unpublished hack, so please bear that in mind when weighing my words, but I am also pretty adamant about not compromising myself.
If you feel that Mensa or RWA, or even the fact that you may be a parent of children and/or goldfish, is important to who you are, I say include it. Sure the agent may not give a shit, but I submit, who gives a shit? I would hope that agents or their lackeys who read their submissions would not reject your idea simply because you added some information about yourself. I know I would want an agent who at least has some idea of what kind of person you are.
It seems that the agent/writer relationship is the bizarre dance of fear-of-rejection and wooing that is the basic foundation for most sales-client relationships. I guess the best advice I can get is try your best to find one that will be straight with you and spare the head-trips so that you both can get down to the business of your business.
(Agents, feel free to check out my blog! I would love to hear what you think - that is if this was appropriate to ask...oh, I'm gonna be 'jected.)