Re: Let me guess...
"Worst case was at a client where a server was rack mounted and several servers were piled on top of it without rack rails. And the bottom server of course needed some physical service."
I once had a similar experience. Customer had a 4 hour response time contract for engineer visits. I go on site and found the server almost totally hidden behind patch cables draped all over the place, back and front. A complete mess. I was told in no uncertain terms that cables must not be unplugged or I'd be in breach of contract. Took a couple of photos and emailed them to my boss. He told me to leave site and emailed their boss and basically told him they were in breach of contract by not providing access. He demanded that they remove the server and install it on a bench before we would attend again. It took two weeks for them schedule enough downtime to get that bloody server out of the rack. Apparently it had to be done in stages and took about eight 1-hour windows over those two weeks.
The chain of director level emails I got copied in on was quite fun to read too :-)