The shop I worked with, we had support on the machines, so Dell would send a tech out to replace a part for the servers that had valid support contracts. We still needed someone on the phone to remote-in to test the fix, of course.

For more complicated problems, our main colo was about 45 mins away from almost all the SAs. We used remote hands for colos that were an airplane ride away, and had varying (read: sometimes really shitty) results.