I'm sure they were and if I had more time to do it, I probibly would have, but it is not neccessary considering they were designed to work in the environment that they are in. I don't think it is the fact that they stick shut that is the problem... it's the fact that where the cable goes into the box isn't an even pull or something because the cable frays and breakes... that has nothing to do with the intake being gummed up.
I agree with you 100%, it is a good thing to clean all of that crap out, but it is definitely not neccessary, there are people on here that have been running over 20k+ miles since the new IMRC without cleaning the secondaries out. They are just going to get gummed up in no time anyway, so to me it really wasn't a big deal.
I did the IMRC replacement and everything works great now. No more egg stink from the exhaust, no more cold run issues, better gas milage, so on and so forth. I couldn't ask more for only spending 30 min on the car.
