Before you pay for one, you can get one for free at the dealership parts counter. I use it because the dog sets things off when he's in the passenger seat.
If it's a puff of smoke right at startup that goes away within seconds, that's most likely oil leaking past the valve seals. It'll cost way more to fix than it's worth. Nothing to get too worked up about.
The system monitors whether the rear doors are opened within 10 minutes before the vehicle is started or anytime after it's running. If you don't open a rear door, you won't get a notification. Or you can turn the whole thing off.
The clip is free at the dealership. Just ask for a seatbelt extender at the parts desk. Or, you know, just wear your damn seatbelt like a responsible person.
You can thank the great state of California for that. The breather wouldn't be legal. I'm sure if you talked to Risk in person, they'd give you a little wink.