Please remember that those groups of ninjas armed with fully automatic real assault rifles did politely knock on the door and ask for permission to come in and rummage around in the sock drawer and peek into the closet where, hopefully, anybody hiding was merely gay and not Suspect #2.
Some may say that when faced with a bunch of ninjas with assault rifles it is difficult to stand in the door and tell them "Come back with a warrant, copper!" Some may even say that the presence of even one ninja with an assault rifle constitutes coersion. But until any complaint winds up in court, all those searches were "voluntary".
Were the circumstances exigent? http://en.wikipedia.org/wiki/Exigent...ted_States_law
In this case it pretty much depends on where you were standing, and how far back from the manhunt you were. If nothing else the cops could fall back on the notion that anybody that would kill a cop certainly would not hesitate to kill an unarmed person thus indicating the hightened level of danger and the increased amount of urgency in finding/capturing that individual. You know, those textbook/dictionary/case law definitions of exigent circumstances.*In the criminal procedure context, exigent circumstance means:
An emergency situation requiring swift action to prevent imminent danger to life or serious damage to property, or to forestall the imminent escape of a suspect, or destruction of evidence. There is no ready litmus test for determining whether such circumstances exist, and in each case the extraordinary situation must be measured by the facts known by officials.
Those circumstances that would cause a reasonable person to believe that entry (or other relevant prompt action) was necessary to prevent physical harm to the officers or other persons, the destruction of relevant evidence, the escape of a suspect, or some other consequence improperly frustrating legitimate law enforcement efforts.
Exigent circumstances may make a warrantless search constitutional if probable cause exists. The existence of exigent circumstances is a mixed question of law and fact. There is no absolute test for determining if exigent circumstances exist, but general factors have been identified.
* - Just because cops have gotten away with that "if they'd kill a cop ..." argument before does not mean every cop-killer case presents exigent circumstances. It just means the courts are more likely to agree with the defense's claim that the circumstances were/ought to have been considered exigent.