Can be tough when you encounter your first godmodding, mary-sue type though. I always feel Pieter is incredibly ordinary and maybe too boring when I bump into the 'Machievellian mastermind genius billionaire' type.
Those are easy; Call the pretentious, self-entitled little twat out on it. Draw attention to their negative sides, underline the bad things about being such a supposedly superior being. If anything else fails;
They are capsuleers now. Just like you.Their origins, their families, their planet-side wealth or position, it's all meaningless now because in space, they are just like every other 'average joe'. Capsuleer-dom is the great equalizer, and any toon that forgets this is just waiting to get pulled down from their lofty throne to be beaten half to death by their fellows, figuratively, verbally or literally, all depending on who their arrogant attitude offended.
They might themselves try to gloss this over, but their fellow peers will know it and reputation is the only solid currency worth anything, everything else is replaceable.