Non Attendance at main IN events - Wager (Istanbul)

I know gambling in Turkey is illegal, but betting is not... we know this through horse racing, football and chance games... so I would like to open a wager (bet). I say that out of the final amount of people that say they will attend, at least 20 % will not. So at the current standings. 87 people will say they are coming, but will not....... so.... who will take my bet ???