Earlier quoted context omitted.
Depending on the details, the "probable cause that someone is committing a felony" exemption is common to law enforcement. Exigent circumstances. If a police officer hears signs of a struggle in your house, he doesn't have to get a judge to sign a warrant before he kicks the door down.
But the way that gets used seems to be the officer somehow smells pot on every damn person they want to violate.
I won't bore you with the full explanation of who won or why, but what I found interesting is that the dog's past performance comes in to play, the results of their testing, time in the field, etc. Also, the k-9 (human) officers are supposed to keep a record of their results to be provided should this come into question (which raises all sorts of things about false positives, false negatives, etc., due to ignored reporting of incidents that didn't otherwise generate paperwork).
I'm wondering now if there shouldn't be some similar standard of proof for police officers. I've never had the "smells like pot in there" pulled on me for any reason, but I almost hope that it happens at some point so that I can poll the officer's record to see how many times he's used that line as probable cause and what the feasibility of that is.