Technically any market that's about someone doing something by a certain time can be an assassination contract, if you think the market will it enforce it that way. Can't do it if they're dead.
It was kind of close to that betting on Trump to not win the last election - $3.2bn was bet on Trump vs Kamala and there was of course an assassination attempt although not related to the betting.
Today they are bribing journalists to report on a bomb.
Tomorrow they will be bribing armies to bomb.
This needs to be banned.