I too am getting hammered with "discovered" logs from this exact same event. It appears that someone created a "TB event" within the West Bend Mega event and all trackable codes were compiled and shared with all the attended loggers of that event. The "event" GC4EZTV, shows 993 records and has 278 Attended logs so far. This list in theory could generate 278 discoveries by each attendee thus generating over 276,000 emails.
This was compounded by "the list" getting posted in a group on FB (I know the name of the cacher that posted it) to generate even more bogus discoveries. What's to stop this list from getting shared even further which creates the possibility of an endless loop of discoveries in the future.
Have I shared a TB list? Yes. However, I have shared a list that I personally compiled at events by writing down the codes with one or two other cachers and it certainly wasn't a MEGA event. Were they at the event, yep.
I too would love to delete the logs, but alas you are correct that there is no possible way to weed out the few that have personally touched it.
I am considering opening an additional gc.com account to transfer ownership of the infected TB to rid my primary email of the logs, which for now is just shy of 100.