Sure it does. You know what the offer will be but you might not know what OTHER offers will be. Yes, I know TechStars and others are before YC, but there can be other offers on the table (other funding, acquisition offers, etc)

Thankfully, YC seems to be friendly if there are circumstances like this (Paul gives an example below).

This works because YC has a flexible # of slots. TechStars has a rough way to go here because, with 10 slots, they can't let a deal linger for a month without a firm answer. I don't think it's malicious on their part.

Unless I am mistaken the valuation offer varies, so you really don't know how much of your company you will have to give away.

I think with most of the groups you know the basics of the offer ahead of time.