You chose who to trade with seeing someone with 100 feedback doesn't mean trusted, just like seeing someone with 0 feedback doesn't mean they aren't trusted. You are the one participating in the trade, its your judgement what to do. If they want to do 500 bond trades, that is up to them, but I know personally I won't find them trusted, that is your call not ours to start limiting it even more, and quite frankly I'm not going through over 20,000 feedbacks to clean them out just because you trade big amounts.