i don't really see an *argument* situation here- simply a difference of opinion- but i would state that SAFETY should always come first- and to deliberatly leave pins in (hoping) that you will never hit one is not practicing safety.
I hit a pin once that broke my needle- one piece of the needle flew up & hit the center of my glasses- and actually stuck in the lens! if i had not had my glasses on i may have lost that eye...scared the crap out of me! i never ever leave in pins now--and teach everyone i am helping to never ever leave them in (& for some people i recommend safty glasses
)
it's bad enough to break needles because of a mechanical problem- its just plain unsafe to leave things in the way on purpose risking injury---it's all fun til someone gets hurt!