You appear to be thinking that problems can typically be replicated in a lab without sending an expert to the remote site. My supercomputing startup (PathScale) made specialized networks for supercomputers. While most problems could be solved with remote diagnostics, I still spent a lot of time flying to customer sites. Sure, you can call it "a last resort", but it's necessary if the problem can't be replicated in the lab.
Agree completely. Sometimes you cannot replicate things in the lab; then you go. But you do this only if you cannot replicate.
I spend part of my time developing large, real time, visible systems and when things do not go as planned there is always a lot of pressure to go on site now and "just fix it". I have taken my lumps to learn that the right approach is to say "no, we will start in our lab".
