I would reaffirm that. I would suggest that with any kind of scheme like a pension plan, what happens to individuals within the plan is going to vary. But what happens to the population is how they determine what the contribution rates are going to be, how much it's going to cost, and what kinds of interest rates they will have to achieve to pay for benefits into the future.
So if you drop out of the plan, then you basically undercut the plan design and you may as well have no plan.