Am in similar situation with wife. Wife has again requested that I accompany her to meeting tonight as I did Sunday. Do not wish to create more tension with wife but do not wish to be exposed to cult influence. I told her I would go with her to meetings in the past, despite my disagreements with the doctrine and methods. The mistreatment I experienced at the hands of the judicials and my [former] family caused me to reconsider.
That being said, a guy like me giving advice would be like...pretty illogical. Unfortunately, there are moments in life where you have a choice: bite the bullet and play politics for the sake of pleasing someone, or stand your ground and don't allow your boundaries to be violated. It'd be great if people respected the boundaries of others; the world would be an awesome place. But...here we are.
Go with your feelings on the matter. Make sure that your choice won't leave you with a bunch of regret. If it's more important to be with your aging relatives, do it for their sake. If it's more important that this is a frakking cult and you want no parts of it whatsoever, go with that and arrange to spend time with your relatives in a more neutral setting, sort of like blondie recommended.