The risk to a founder is having the debt called and not being able to pay it back and/or having the valuation of the company not where you'd predicted - depending on the terms a founder could actually lose their company in this case. NAL.
Really it just seems _too bad_ for the employees and cofounder that feel like they're getting screwed. It isn't like "get it in writing" is a new concept though. I'd guess they either drank the Koolaid early on or they had a gut feeling they were getting screwed for years before this all came out. Either way, a shitty place to be in but not new or uncommon with cut-throat founder/investor types.
They should go found companies themselves! Get a big ol' piece of the pie!