I would like to go to all the "recommended" motel rooms about a day before the a$$embly bookings, gather up all the bedbugs in all the rooms, and turn them all loose in the Governing Body's headquarters. Then, when they complain, I would tell them that you wanted the witlesses to get these same bedbugs. Good enough for them, good enough for you.
Actually, I believe they are getting kickbacks. When an organization books a block of rooms, it is common practice for the motel to give back a percentage of the revenues in exchange for the business. Of course, that is reflected in the price (which is why it is sometimes possible to do better on your own). Any kickbacks they do get go directly into the Worldwide Pedophile Defense Fund. Which is one more reason to, if you have to go at all, to make your own arrangements. You may (may) have to pay an extra $10 a night, but you might also save that or more on gas alone. And I would rather pay $60 a night for a motel room that is clean funded (all of it goes to the chain itself) than pay $50 a night, even if I saved nothing on driving and got the same quality, knowing that even a penny of that could end up in the Worldwide Pedophile Defense Fund.
So they give you a hard time about it. One thing that might work is, if they start hounding you about the room you book, you threaten that you won't be going at all if they continue that attitude. Be prepared to make good on that threat if they hound you again. Then book a room independently, without referring yourself as a delegate. They lose the kickback they would have got (so it won't go into the Worldwide Pedophile Defense Fund). Other hotels might see that signing on no longer guarantees full bookings, and that will create rooming shortages (at least official room shortages) in the future, which in turn will cause other delegates to book without that damn list. Either way, those kickbacks are going to disappear.
All said, the simplest and most effective way is to just not go at all, if that's an option.