Quite sneaky… It's also here so probably not a typo or misunderstanding: http://www.marriott.com/rewards/member-benefits.mi

"¶¶¶ Room Upgrade: At no additional charge, we’ll do our best to upgrade you to our best-available guest room in the next room category level. Suites are excluded. Not available at Marriott Vacation Club."

Even less incentive to reach MR gold now…