I think the earlier stage you are (seed, angel) then yes, there is definitely risk for a large class of employees. You're taking a risk on the founder's ability to execute, joining a company that is not cash flow positive and tying your mortgage payment/insurance to their ability to raise money in the future... it's derisked in each successive round and startups/founders are not all equal, but I think if we're talking 1rst employee it's fair to say there's some risk.