I know I thought about being a Rho Chi, but our president at the time made a decision that since we were one of the smaller groups we should all stick around for rush to fill the room and not have to disaffiliate. I don't think it really helped
but that might be one of the reasons your sisters don't want you to do it.
Since then though, I think our Panhellenic has passed a resolution that each sorority has to have x number of sisters serve as Rho Chi's, which I think is a good idea.