1. Very unlikely to be turned off unless they are out of service for technical reasons. ATC knows we use them as a backup and they like it, especially when running parallel approaches.
2. ATC expects you to follow the instructions they give you if you go around. Very few major airports will want you to fly the published missed approach, even in IMC unless you lose radio comms. In that case if you're on a visual approach, and you need to go around and you lose radio comms (super bad day), you're supposed to use your best judgment. I would squawk 7600, fly a visual pattern/circuit and land with a steady green light from the tower.