I don't know the particulars of the case, but I beleive that they merely had to open the door and look in. It was the living room where the "activity" was taking place. Does this matter legally? Should this matter legally?
Interesting question. If one feels that people should be allowed to engage freely [with regard to society's laws--not with regard to Judgement Day] in non-commercial sexual relations provided that (1) they don't violate things like marriage contracts, and (2) they take reasonable care to avoid discovery, then the two questions that arise in this case are: -1- Did the police do anything illegal, given that they had what they reasonably believed to be accurate information about a crime-in-progress?
-2- Did the men take reasonable care to avoid discovery, or would reasonable care have required that they either undertake their activities away from the entrance [which they may have done, I don't know] and/or lock the door?