I received my Bentley manual after the fact, so I didn't know better, but I simply removed my front seats without incident. I was 'alarmed' after reading that I needed a special tool to prevent deployment, but the fact of the matter is that they did not. I didn't disconnect the battery, but I didn't have the ignition turned to 'on' either. Blind luck on my part, but fortunately good enough here. I removed them to remove my waterlogged carpet and reinstalled when the new carpet arrived.
Thinking through this, though, you'd have to remove the seat before you could install the device anyway, right? I mean, the device plugs into the airbag wiring harness, so you'd need to disconnect it prior.