sugarmagnolia:
Accidental huffing will only lead to a minuscule amount of butane actually being inhaled. If you do it purposely you will most likely inhale a higher volume of butane. This is why it's not an issue if you inhale it accidentally, the amount is so small that it will not have any detrimental effect. It's okay not because it's an accident, it's okay because by it being accidental the amount is lower.

LonFFW:
Just chill dude, you were able to feel the butane in your lungs? Sure thing. You didn't notice it before you got smacked because it wasn't there... you started to smell and feel it because you were stoned and thinking about it. Like a placebo, if you think the sugar pill will heal you... sometimes it does.