So, a very high level, low average pro or less... Say, for example, a level 90 pro with a 58 average or similar (not sure I have seen many).
I would think it's possible, I guess, if the person has played a hell of a lot of practice rounds and gathered the needed amount of xp to continue leveling up. Of course they have the option to buy their way to level 64 at $2 - $3 a level. Figure playing one or two ranked stroke play rounds with an outstanding score say on a par 34 course like the front 9 at Oly. Since averages are based on par 36 when playing 9, and then doubled to 72, they already have a 4 under average just by shooting par. Let's say they make 5 birdies. There is a 58 average right there. ( am I confused or is this correct?)
I could be way off base there, but the temptation for some to start playing pro level ready go's from the short tees all dressed out in level 90 gear is just to great... It just seems too obvious to me, but like all the guys/gals that replied already said, they think they can beat the system at our expense.
So in short, they don't want to tier up because each time a pro turns master, and master turns legend, the holes get much longer. Thus harder to play with lower level equipment.