Also, the default case sounds like a real loser for the investor, the chef in the story. If the owner defaults, there's a good chance that the business is not performing to plan, so the chef gets a share in something that's not worth as much. Also, the chef now owns part of a company with an owner who is not planning to sell the business, and who has complete control over how it's operated -- he's now got to try to sell that 15% on the secondary market, where it will probably go for pennies on the dollar. If he holds onto it, the founder has no obligation to share profits with him, so there's no ongoing revenue, and he has no long-term assurance of it ever becoming liquid.
What a mess!