OK, here is how it works.
. . . you place a credit card on file for room key charges
. . . key limits are $500-Values, $1,000-Mods, $1,500-Deluxe/DVC
. . . you charge purchases, tips, etc to the key
. . . the charges accumulate to the limit
. . . when the limit is reached, charging is suspended
. . . you call or visit Front Desk, and the credit card is charged *
. . . this clears the room key balance
. . . THIS IS NOT DONE AUTOMATICALLY
. . . your charging limit is re-established for room key
* You might be in the park when this happens. Just ask the cashier
to call the resort, and you can ask the credit card to be credited.