(yes I have had to, given a faulty nic in an LB in front of 4 dns servers *sigh*)
And having a copy on the phone is total win.
Having a cop pull up behind you, parked on the shoulder while you fix things, is kinda cool, especially when she says "Thanks for pulling off the road to do that."
Oh - and the GPRS bit? -- depends on which slicing your network uses by the way.