I don't condone the SC's behavior at all. He could've been a lot nicer. However, I do understand the frustration of something being wrong when you're using the vehicle and it not showing up when getting checked out. My remote start and locks were giving me trouble, and whenever my parents took my car into the dealership, they always said that it worked perfectly for them. I no longer have remote start or locks because they crapped out shortly after, and it was just outside of warranty.
As I said though, no reason to be a jerk.
In the repair center, we called this, "technicianitis," because the customer brought the product in with a problem and for the tech it would behave perfectly. Not the customer's fault, because a) we're talking shop environment and b) the worst sort of problem to deal with is an intermittent one. I had to occasionally ask customers to bring the item back in when it finally crapped out, because the tech could not force it to do it's "trick," without using blunt force trauma.
BOM3, however, was a sucky for taking an attitude with G. I mean, it could be an intermittent problem or *gasp* another part causing the problem all together! He could have just done the grown up thing, accepted that the problem couldn't be recreated and moved on.