You might think about embedding bounties in crypto blockchains. For example, create BTC wallets that can be unlocked using a secret sitting next to (or steganographically embedded in) the secret you're trying to protect. This gives the person uncovering the secret an incentive to activate the canary. {RI,MP}AA are apparently doing this with their music and movies, so they know when they are showing up on pirate sites…
There’s a reason companies use bug bounty platforms instead of just having a bunch of bitcoins lying around.