Change DB:

According to "The Who Concert File," Led Zeppelin attended the opening night of The Who's one week run at the Fillmore East featuring their rock opera "Tommy." According to the book, after the 10/20/69 show there was a party hosted by Bill Graham at Max's Kansas City, a popular NYC rock club. Led Zeppelin and The Who spent "the rest of the night in long discussion."

Since Zeppelin attended the show and partied with The Who on 10/20/69, they couldn't be in Seattle playing a show.

For this particular situation I would just delete the date. The evidence ways very heavy in favor of a performance not being performed in Seattle on 10/20/69:

1) The Who concert
2) At this point in their career, especially with no "Starship," it makes absolutely no sense for them to fly back and forth across the entire U.S. for just one show in Seattle. They could have easily scheduled it around the SF dates in November.
3) There has never been any shred of evidence that this gig was played (ad/review/handbill, etc.)


I also think the 10/23/69 show you have for the Seattle Center Arena was never performed either (for reasons 2 & 3 from above)