Consider how you feel about your own children and it might help you feel a bit more at ease.

I would although I would feel a little uncomfortable, I know my parents would find a way to help even if we didn't accept (ie. at birthdays, replacing things of theirs early so they can offer their old things to us etc). My dad always says that when they die, the money would end up ours anyway so they would much rather see us use it when we need it. I'm very close to my parents, admire them greatly. They allow us the means to do things with them we wouldn't be able to afford otherwise (holidays, visiting family interstate, meals out) so they enjoy that aspect. Another thing that they made sure we knew though is that any financial contribution doesn't buy them any rights to influence decisions (they have spoken about helping with the girls education but they also said it is our choice where we send them for example). My parents also often buy us things we could live without but greatly help improve our quality of life (eg a vacuum cleaner).

I have to say, I think it is odd that their would be trouble amongst siblings over it. I guess I am close to my brother because I've never felt that way even when he was bought a car during highschool to help him get to and from his work. I didn't get offered a car till 5 years later when I was pregnant with DD1. It made sense, I didn't need one before then! Same with him living there rent and bill free, it doesn't bother me and I'm sure it doesn't bother him that my parents help us out between rentals (paying the new bond while we wait for the old one) or helping with Obstitrican fees etc. Different needs and all that. I love my brother, I only want the best for him and I can't say I've ever bothered trying to work out who is getting "more" from our parents lol.