UPDATE: Anton Troianovski of the Wall Street Journal followed up with the Plattsburgh police on this, and was told that the volunteer actually damaged his tire on a broken bottle.
An old union trick is to wedge broken glass bottles forward of the rear tire and behind front tire, so no matter how one leaves a parking spot one of the tires runs over broken glass.
Whoops! Too bad you missed seeing that glass.
Roofing nails are also used.
So the glass doesn't necessarily mean it was "just an accident".
“the volunteer actually damaged his tire on a broken bottle.”
Someone gets a flat tire and immediately thinks funny business?
Sometimes people just need to take a breath.