It's like the "smell of marijuana" for cops. I'm convinced that the reason (right-wing) law enforcement is against pot legalization is because it removes this excuse, along with "the dog alerted" for arbitrary searches.
Meth and crack also have an odor after smoking them and dogs already can alert on them even when they aren't smoked. It's already a commonplace lie and there's no repercussions when a search turns up empty so why wouldn't they just keep lying? Or even easier, just claim they smelled alcohol.
Police will continue with warrantless search and seizure until they actually face repercussions for misconduct.