Revoke button deletes data without a confirmation prompt

We have experience two incidents in which a teacher has inadvertently clicked the revoke button to the right of the appointment with a result that the slot and all student booking in that slot are deleted. Ideally, there should be an option to hide that button (see note below). However, at the very least there should be a confirmation button before the deletion occurs (as there already is with the delete button).

Note: I have hidden that button for now by patching the plugin. Unfortunately, due to a change in hosting arrangements we will lose the ability to do this ourselves and not sure if our new hosts will be willing to do it for us so something that allows all users of your excellent plugin to be protected from mistakes that result in unintended data loss would be welcomed.