So what if i make this a challenge combined with a lottery?
Brainstorming:
I send a copy of the extracted keyfile for let's say 0.05BTC
Everybody that 'buys' the keyfile is put on a list, and if someone manages to crack the passphrase, the contents of the wallet get divided by all those users.
More than likely most would just buy a spot on the list and do nothing.
Small price to pay for a bunch of
BTC