At first I read "bad breathalyzer" as one that tells you to use mouthwash, and not as the assumed intended bad=bogus wording.

Around here they are just used as part of a first step I think: if you fail it you'll be asked to go for a alcohol blood test.

And around here, they’ll just take you to the station for a more advanced breathalyzer test (Canada). Even though the police can compel a blood sample through a hospital, they don’t bother because the law doesn’t require it for a conviction.

I wish I could remember the source of the statement: "To search someone's vehicle, a police officer needs a warrant signed by a judge or permission from a dog."

Well said, but in fact they don't need even that. They'd just say they smelled "strong marijuana odor" (the proof it isn't happened now on you, and how exactly you're gonna prove they didn't smell that?) or that a confidential informant (local junkie) told them he have seen a person looking like you doing whatever they want to accuse you of.

Qualified immunity pretty much guarantees there's no punishment for any shenanigan as long as it can be plausibly presented to a judge as the police believing it's lawful (it doesn't need to be lawful, just belief is enough). The worst they risk is evidence being excluded - so no risk at all vs not searching.

Subtly different situation -- a dog sniff is only an indicator of probable cause, while a breathalyzer may be presented as evidence of guilt.