Sparks and loud pops on the train are fine if they stay outside the passenger area. Kind of neat, actually. Add a bit of piquancy to the commute.
Much less dangerous, too, than silly women who wear stilettos without knowing how to walk in them. The girl next to me (She was wearing nice flips that showed off a new pedicure. Made me glad I've not broken out my sandals yet. My feet need lots of work before they can be exposed.) was stepped on by a woman who lost her balance getting up for the next stop while the train was still moving. What a scream. What a scene. Poor thing.