If discovered outside the bounds of an administrative search, then I would agree. Otherwise, absolutely not. Our rights under the Constitution protect us from unreasonable searches. As such, if it is an unreasonable search, then everything that is gained from that search may not be used in a trial, even if that means the accused gets away with murder. That is a basic tenet of our society that many still do not appreciate.

An administrative search is non-consensual in nature and as such is only permitted in very limited circumstances so that it is not unreasonable. The courts have said that you can only search for the items directly related to the purpose of the administrative search. So if the search is trying to see if you have an elephant, the government agent can't search your wallet since an elephant can't be hidden in it. Anything incidental to a proper search may be seized even if unrelated to the search.

So if a TSO sees a potential prohibited item via the x-ray and calls for a bag search and then the bag search discovers pounds of illegal drugs, then that would be okay. However, if the TSO just sees pounds of illegal drugs and no prohibited items, then a bag search is not proper (however, in reality, a TSO can almost always say the he saw something that might be a prohibited item). Ever wonder why TSO's are not given any training in the identification of illegal drugs? Because then the administrative search may not be valid if drugs were found.

And welcome, Scots_Al!