I heard the story on the radio this morning and believe I recall hearing that the agents only suspected certain illegal activities were taking place in the room and did not yet have enough information to actually get a warrant. This tactic was employed to enter the room, survey the environment, and gather information that they then used as the basis of a warrant. Also, they did not mention in the warrant request specifically how they obtained the information (by cutting services and entering the room via that approach).
I am not making an opinion on the matter either way, just adding context that I heard from the story.
Sounds like fruit of the poisoned tree to me. Their probable cause was obtained in an unlawful manner. A police officer (federal or not) cannot enter a premises under bad faith to gather evidence. Any evidence obtained in that manner can't be used against the defendant, nor can it be used to get a warrant.
I worked in law enforcement alongside detectives for 14 years, and they were always very careful about probable cause and evidence gathering, because they knew the risks to the case they were building if they didn't do everything on the up and up.
Why the FBI wants to risk blowing what is obviously a very important case using illegal evidence gathering techniques is puzzling. The fact that the Justice Department is apparently in on it is even more mind-blowing.
This is something that happens a lot in television and movies (Cop 1: "Did you hear screaming behind the door?" Cop 2: "No I....oh yeah, someone must be in DANGER!" Cops kick in door and see evidence for their case), but not so much in reality.
I too find it troubling that the Supreme Court upheld the government's position that it was a valid search.
I actually think the search was valid (and remember McGacken consented, which was a public-spirited action). What bothers me is that in establishing that a potentially serious crime had not taken place, a victimless one resulted in a pirson term. McGacken did the morally right thing in allowing the police officer to verify that nobody was in danger, and while I can't really fault the police officer for doing his job, I wish he had looked the other way.
What really bothers me about it is that I can't articulate a clear legal principle about when prima facie evidence of a crime should be thrown out for moral reasons. You could say that if you're investigating one crime then discovering another one incidentally shouldn't count, but what if the police officer had been investigating a report of illegal marijuana production and had discovered the rape in progress? Of course we'd want that to be prosecutable. We could wish that the war on drugs were over and nobody would be prosecuted for Marijuana, but I can think of other petty crimes that would substitute equally well, eg if McGacken was a petty thief or something. It's a really tricky case to me. I'm surprised nobody has examined it in a law review article.
It seems like we could establish some hierarchy (in fact, we already have one implicit in maximum or minimum sentence lengths, though I don't know if that is the right one to use). When an officer asks to engage in a search, he can then state "I am investigating X, we will ignore anything less serious."
If something is seen, it seems like it would be hard to prevent the officer from making a mental note to look into that guy later. We could grant immunity, but that could also get weird. I think just narrowly excluding the evidence uncovered in the search would still probably be an improvement, though (probably...).
I am not making an opinion on the matter either way, just adding context that I heard from the story.