I'm guessing it's not common practice but it makes sense. It should not be that hard to do so. Being able to see the area the pickup is in before cutting will make things much safer. How thick is the floor? What's it made of wood or metal? If there is a metal plate you might want a good shop to do it. A multi tool might be the tool of choice with wooden floors. Pictures would help. Till you know what you are dealing with. Do not do a thing.