I had an "Apple genius" come out to the office for a service call, as it was under warranty (I had to pay for him to come out, though, as you are required to bring in your equipment). After being unable to resolve the problem he dumped it all and blamed it on the router, which he wouldn't touch, though this was the only computer that would not work.
I didn't even bother to repeat the procedure on my home network as it was the same laptop and I'm sure he would have determined the router was at fault there as well.
I wholeheartedly agree with your premise, though.
