Someone goes to the lesswrong community weekend for 2023, and conditional that they test positive, they will find it difficult to travel back, not because they are very sick, but because you are by law or social pressure not allowed to return to their home country. Such as airlines banning anyone with covid symptoms.

Does not count if they can't return due to being sick, but would be allowed to return if they were healthy.

The event has 150 people, there will be testing on everyone before entering the event. If someone tests positive, they will not be allowed to mingle with everyone else, but will either have separate accomodations arranged or travel back to their home. More information here: https://www.lesswrong.com/posts/f2vFYmwFGu3HLL9QB/lesswrong-community-weekend-2023-applications-open

If no one ends up testing positive at the event, the market will resolve No.