Susan, I suspect that Graham found those problems at a sound check.
Unfortunately the house engineer with an attitude is a problem that does occur from time to time. Most are very flexible though, and I tend to find that the more they know, the more flexible they are. The awkward ones are generally the ones that are not that good, and feel they need to protect their pitch in some way.
At a couple of gigs I've come back to the desk to find that an elephant trap has been left for me between completion of sound check and the performance ...
Luckily 99.9% of them are great to work with.