I agree with you generally but taken to the extreme this argument very easily goes to "precedents I agree with should be venerated because they're precedents and precedents I disagree with are wrong" silliness.

"Precedent is often crap" isn't really the basis for any cohesive judicial philosophy or legal thought process.

I'm not aware of any precedent anywhere that approaches "ALPRs violate 4A" territory, it's when other stuff happens that's beyond simply "$lp_id was seen by $camera on $datetime" that I've seen courts start to talk about reasonableness and privacy.