[adjkant]

Because there is an upper bound for most candidates, and there most certainly is a lower bound if the company means to hire fairly to employees. But as others pointed out, most companies do not have an unlimited upper bound. Additionally, companies do not want all senior level superstars, they almost always want the balance of levels. So be honest with those listings!

> Especially with a well known company like YC, it seems like they would have a solid lower bound so there's no need to list it.

That sounds like a great way to exploit the subset of candidates that don't know the unspoken rules of the valley. And given the variance of companies in YC, I don't think there is a known lower bound for every company.