This might be a good idea for perhaps one hole at a course, otherwise, it might really slow things down. Personally, I'd like to have a chance to spend $5 to win $20K.
i agree one hole would be good, or at most two (one of the front and one on the back). if done properly, i don't think it will slow play down much. there are much bigger issues to deal with that slow play down more. (like not playing ready golf, looking in the woods on every hole for lost balls, lining up 3 foot putts). honestly, i think the beer girl slows play down more than this would. this should be a quick insert of your money and then go hit. most likely the other 3 in a foursome will have their bets placed before the first one has teed off. and if no one hits it within the flag-stick or gets a hole in one, you move on and play like you always do.
i think this could be a great way to keep struggling courses from going under and help keep costs down.