Originally Posted by milesrunner

Here it is:

A Membership Account may be closed at the Company's discretion if no Points or Miles are accrued during a 24-month period. All Points in the Membership Account will be forfeited at that time.

From one of many of the Marriott rules pages. So not only do you loose your points, but your account "may be closed." That's rather harsh. What about your lifetime stays?