As many games and other applications, a lottery needs a reliable random number generator. Especially when the prize is high. There are some sophisticated algorithms to achieve this goal, such as Commit-and-Reveal.
These algorithms rely on multiple random sources, which are rewarded for revealing a secret they shared as encrypted in the first place.
As discussed here and here, among other places, these random sources must first commit a certain amount of ether, which they get back in addition to the reward at the end of the process. This deposit serves one major goal: making sure the contributors reveal their secret, as they might refuse to do it to serve their own interest.
To be effective, this deposit must be related with the winning prize of the lottery. For example, if the winning prize is, say, 1 Methers, it does not make any sense for the deposit to be only 1 ether: a contributor would rather lose it if that can help him getting the prize or even a fraction of it.
Unfortunately, this model probably cannot work with very high stake. How could we find random contributors willing and able to block such a high amount of money?
Although economical answers might definitely be interesting, I'm rather looking for technical solutions to reduce the deposit requirement constraint.
PS: I'm not really interested in lottery in particular. Any high stake scenario would be.
PPS: Although this question applies to the blockchain technology in general, one would certainly want to implement such lottery on Ethereum, so posting it here probably makes sense.