That's a really good question. I see absolutely no downside to an elevator being set up to cancel a floor button by simply pressing it again. I work with a lot of industrial controls and doing something like this would cost almost nothing. Assuming elevators now a days use some sort of basic PLC controller you could do this in an hour by reprogramming the logic.
Some if you quickly press it twice its canceled, though i don't know why this is so rare
And some you can press the floor button twice while holding the Open Doors button in.
They do if you have the right key with you.
That sure opens up opportunities for assholes! There's a lot of people who would just cancel everyone else's floor to go straight to their own.
Safety.
You don't want someone to nefariously bypass your floor to take you to a floor of their choosing.
That's a really good question. I see absolutely no downside to an elevator being set up to cancel a floor button by simply pressing it again. I work with a lot of industrial controls and doing something like this would cost almost nothing. Assuming elevators now a days use some sort of basic PLC controller you could do this in an hour by reprogramming the logic.
Exactly how it's done in my building
It's a safety thing. So nobody can just bypass your floor and kind of abduct you.