I am not a big fan of discussing very general matters when there is a very specific subject to be discussed , theymos clearly stated this
"Risked BTC" is how much money you could have lost if the person you're rating had turned out to be a scammer. Or, if they are a scammer, it's how much you
But then he does leave a risked
BTC amount which he could not have lost ( assuming my previous theory is correct ) , so this does not seem to me like Theymos put that point for us to follow and for him to ignore, it just doesn't make sense, therefore the only explanation I can think of is that he did not mean that it has to really be "YOU" trading with that member for you to be able to use the risked amount.
You can come to whatever conclusion you want...
Indeed, we all can.