Home made kayak rack-safety question

I'm constructing a kayak rack to transport a tandem kayak upside down on top of my 2006 Prius. It will consist of two PVC and foam cylinder shaped pads to lay across the top (one front, one back), and they will be temporarily attached using nylon cam buckle straps that will pass through the foam pads and pass through the front and rear door openings and will be secured inside just under the headliner. Other cam buckle straps will hold the kayak onto these secured pads.

I have three questions to which I hope someone will have an answer:

1. Other than the side airbags not working properly with the straps going across them, are there any dangers should an airbag deploy other than not getting the benefit of the airbag?

2. Is there any way to temporarily disable the side air bags?

3. Any better ideas out there than mine?