I don't think any of the sensors are going to be functioning if the motors aren't fired up. In fact, I don't think they start beeping about being close to ground until you take off.
The thing I'm wondering about is gimbal behavior. You can switch between Follow and FPV mode in respect to the gimbal tilting with the craft, but it might still keep level with pitch (something I would not want), so you couldn't point your camera up or down without gimbal resistance -- how does that work?
Chris