No. It's not the employers fault that Alice spent more money on her mode of transportation.

This is why paying people for their commute is unreasonable. Payment by mileage is based fuel costs mostly. Some wear and tear, but mainly it's to offset the fuel cost. If someone rides a bike to work, they don't have fuel costs, therefore should not be compensated.

If it's true, does it really matter where it comes from?

Nuclear is the way to go.

How about not giving the parents the teachers' personal phone number for starters. Every and all contact should be through a school email or chat app.

And any email from a parent harassing or threatening a teacher gets escalated to the principal.

If it continues, the pupil is expelled from the school

Pretty much like a car these days