Only at Slashdot would parent be marked "insightful".
You do realize, of course, that there are a wide variety of situations wherein a LEO is allowed by the law to enter a home without a warrant, I assume.
Probable cause, for one. If the police follow a person fleeing a crime into a residence - or virtually anywhere else, for that matter - they're acting well within their rights and duties and no warrant is needed.
An Arrest Warrant - No search warrant is needed if officers have an arrest warrant and the reasonable belief that the fugitive is inside. Even if they find evidence for crimes unrelated to the search warrant, the evidence is still admissible. See e.g. Gaskins v. U.S., 218 F.2d 47
Consent is another. If the homeowner has provided their consent, then the Police are well within their rights and duties.
The Open Fields Doctrine is another. If objects are left in plain view in an area not traditionally secured as private, the police are well within their rights to search these areas. See Oliver v. U.S.
And the list goes on. And on. And on. Contrary to what you saw on TV or what your high school civics teacher improperly told you, a search warrant isn't always necessary. In fact, interfering with the police in the above situations can easily get you arrested, but you'll at least give the judge a good laugh as he hears you argue the 4th Amendment as a defense.
And what if the search or wiretap is illegal? If you're truly a criminal, if you've truly done the things you are accused of doing, then you may have just hit the jackpot. Under the exclusionary rule (subject to its exceptions, of course), the evidence is tainted, the "fruit of a poisonous tree," and likely inadmissible as evidence against the target of the search in any case.
IANAL - just a 3L (and I haven't taken Crim Pro yet, so don't be cruel, but if you have an actual understanding of the law, please correct me where I am wrong). But of course we have internet lawyers here like parent who just love to make these ridiculous arguments.
Look, I'm not fond of cops. I can't think of anyone who has ever been to law school actually worked with attorneys and seen what the police often do could be fond of them. But following suggestions like parent's is foolishness indeed. Want to support your local public defenders in making illegal search arguments? Please do. chip in some cash, they could use the money. But don't run about harassing the police as parent suggests.