Toyota will be sending out letters on Nov. 2nd to owners of said Siennas explaining the problem and offering to fix it. To do so, Toyota will offer what it calls a "warranty enhancement" to these vehicles, covering the cost of these door repairs on Siennas up to five years old with 100,000 miles or less. Though a bad spot weld on the door check mounting panel would normally be covered by the Sienna's standard warranty, that only lasts 3 years or 36,000 miles. Toyota has also said that it will reimburse owners who have already had the doors repaired on their own, in some cases at the cost of thousands of dollars.
Curiously, Toyota is not calling this a recall. Of course, what automaker wants to refer to a problem with one of its vehicles as a recall if it doesn't have to? As long as Toyota takes care of the Sienna door problem to the satisfaction of its customers, they can call it a Happy Happy, Joy Joy Service Encouragement Bulletin.
Thanks for the tip, DarkKnight67!