Well, it's something to do with the ship having some kind of very important mission. And because they want to finish that mission they go with the ship, but they cant see where the ship is going and would never be able to catch up again if they would leave.

That explains them staying, but it's still just.. Weird.. Technology has never stood in the way of what is and isn't possible in Stargate. :P Get some Mckay to hotwire the damned thing already and voila. Or whatever.

Like I said tho, will have to see how it playes out when they launch, I just find the whole plot a bit dodgy. xP