“Because the boys are asking for the money after the chasunah, not before. :)”
The boys are asking for a guaranteed payday. This is no different than this new NASI initiative which is guaranteeing a payday to the shadchan. The only one who has no guarantees of anything, and it is her and her family who are putting up all the guaranteed money for both the boy and the shadchan is the girl and/or her family. At least use some of this money to guarantee her a date!
I am suggesting releasing some of that money to encourage dating. $5000 or $5,000,000 in a secure escrow account is meaningless if a girl doesn’t date.