Re-read the OP.

Supposedly, the courts have upheld that TSA can't actually search for drugs, but if they are looking at something else suspicious and just happen to run across drugs, they are required to summon LE.

So: supposedly the TSOs saw something that looked like a potential threat to aviation security in this bag (which is what they are supposed to be watching for). They pulled the bag to investigate this suspicious item(s) and just happened to find drugs that had to be reported to LE.

Question still remains: what potential threat to aviation safety caused them to pull the bag in the first place? Or was it just a random bag search? Did they see an object that looked like a grenade? a handgun?

Or did they see weed and pull the bag solely to investigate the weed?

FWIW, a truly random bag search would be a search of a bag flagged prior to the xray.

They are allowed to search for anything on the list of prohibited items for aircraft.

Which is why marijuana was added to the list.

They don't have to have a reason beyond a clerk asserting that they "saw something." That's all it takes for them to open a bag and "discover" pot.

Cite?

That is not what the OP's cite says.

It says what we already knew: they are only 'allowed' (officially) to search for WEI. IF they encounter non-WEI contraband (marijuana, for instance) during their authorized search for WEI, then they have to notify LE. They can have ETD technology and explosive-sniffing dogs because explosives are prohibited. They are not supposed to have drug-sniffing dogs, because marijuana (or large amounts of currency) are not WEI, do not present a hazard to aviation security.

TSA has a statutory mandate which is pretty much WEI only. Some screening of people, too. Adding Marijuana to the list of prohibited items no more expands their statutory mandate beyond WEI than adding pink striped socks to the list of prohibited items. But an agency exceeding its statutory mandate is not necessarily a constitutional violation, and that makes it all the more difficult to detur agencies from exceeding their statutory mandates.

United States v McCarty gave TSA a pretty good roadmap of how to conduct themselves so as to make any potential evidence 'discovered' during screening admissible. But if TSA had to defend putting Marijuana on the prohibited item list in proceedings under the APA, it wouldn't be an open and shut case.

Whole body scanners fall outside the court prescribed limits as well (they are not the minimum amount of a search necessary to find prohibited items--nevermind they have been shown to be ineffective anyway). Yet TSA has no problems using them.

All TSA would have to say is that marijuana is an organic substance that can burn, fires are a danger to aircraft, and thus marijuana is dangerous to aircraft.

You can complaint about it all you want, but no court in recent history has put the brakes on anything the TSA has done.

The government has been violating laws for our entire lifetime. It's a big part of the picture of why the judiciary finds that the government has been on, or is on, the wrong side of the law. Apparently a government remains legitimate despite violating laws.

That isn't fair. I agree with you that the Fourth Amendment requires TSA's administrative search to effect the least amount of intrusion necessary, and I also agree that the body scanners go beyond that, but the DC Circuit ruled that body scanners don't violate the 4th Amendment. The issue of "least intrusive means" was not properly argued to the Court in my opinion.

Fofana did. But that's about it. The DC Circuit said TSA skirted the rulemaking process violating the APA, but that the body scanners don't violate the 4th Amendment. Probably the same for the prohibited items list which means it could be litigated, but it would be difficult.

And so is tobacco, but it is not considered a prohibited item. Neither marijuana nor tobacco is a WEI, so the TSA has no authority to place it on the prohibited list unless it wants to include every combustible on the planet as prohibited (which would include books, newspapers and magazines).

But they did it . . .

Yet they still don't train TSOs to recognize marijuana, so what is the purpose? Can the TSA hold the marijuana like they hold liquids and small knives?

I wonder what will happen if the Federal Government formally agrees not to enforce federal law in those jurisdictions in which state law permits possession? For example, what would happen on my flight from DRO-DEN this month currently and if federal law is no longer formally enforced in the future if another passenger is found in possession of marijuana.

That's a pretty big "if". Don't hold your breath.

Don't you mean "don't inhale"? :D

What happens at SFO? The City of SF/ SFPD policy is to allow up to 8 oz. for passengers with prescriptions at SFO. If SFPD is called, they simply determine if the passenger has an effective prescription. Does the TSA then confiscate the medicine after the SFPD comes?