I guess that would depend on alot of things. Who is to say he hadn't had the boat for a while and was very used to it and just went up or down an inch in prop. Also, it doesn't sound like twins, so is 75 mph in a 30' boat all that wild? If he had stock power, like a 496 ho, that would be about WOT.
I think there are just too many variables to criticize this guy as being reckless. If nothing else, who does top end speed runs in a 30'er with 4 people on board? Might not make much difference in a 42' MTI, but the Y2K is a little more succeptible to added weight.