NMC - your friend is for the most part correct. Air displays look quite punchy and generally involve a fair amount of G, but generally the aircraft involved are not carrying stores, and will often be fairly light on gas in the case of larger aircraft. One way of thinking of fatigue is like a weights session in the gym. It's the number of reps vs the amount of weight carried (where weight is of course dependant on the mass of the aircraft and the amount of G pulled). So a light aircraft will induce less damage to its' fatigue life in the same display than a heavy a/c.
That and the fact that display pilots only last a few minutes
