How a single booth incident actually unwinds
An attendee at a two-day convention develops a localized infection three weeks after a piece was completed. She reports it to her physician, who documents a likely link to unsterile technique. She then contacts the promoter, not the artist, because the promoter's name is on the ticket and the show's marketing.
The promoter's first move is to pull the artist's file: license, professional liability certificate with a stated BBP grant, and the signed booth agreement naming the promoter as additional insured. If that file is complete and current, the claim routes to the artist's professional liability carrier and the promoter's event GL is never triggered. If the certificate on file had lapsed two weeks before the show, or never carried a BBP grant at all, the promoter's own policy becomes the only responsive coverage — and it was never rated to carry a bloodborne-pathogen exposure.
This is why verification at badge issue, not collection at booth signing, is the control underwriters actually credit. A folder of certificates nobody checked is not meaningfully different from no certificates at all.