Of course no fee, fee will be counted only if the orders filled!
Then nothing refrains people/companies from placing and removing thousands of orders per second?
Exchanges could also charge for that.
It will never have happened because you are trading in the centralised exchange site, the exchange has no right to charge those are cancelling their orders.
Because that means if their orders haven't executed by the system and then their funds will be back to the hot wallet again. Fees only applied when your warrants get executed.