I've dealt with a similar situation. The CEO claimed he wrote a business plan, validated the idea (some hackweekend where only the idea was presented, no protot

I've dealt with a similar situation. The CEO claimed he wrote a business plan, validated the idea (some hackweekend where only the idea was presented, no prototype), will quit their job and put 20.000 Euro into the company (can't remember the exact number). I countered that, sure, I'll put 20.000 Euro for 50% of the shares. CEO didn't like it, apparently the soon-to-be company was already much more valuable. In fact he gave up shortly after so value went to 0.