Receiving an anonymous tip or hearing a rumor about you is not enough evidence for police to get a search warrant for your house. Instead of taking the time to do a real investigation to determine if the rumor is fact or fiction, the police will perform a "Knock and Talk", also known as a "Tap and Rap", on your front door. Their intention is to trick you into opening the door so they can claim an odor of marijuana is coming from inside your house. Police will lie and say they smell marijuana when they don’t. After detecting the supposed odor, the cops now have probable cause to enter your home and detain you while they get a search warrant.
To counter this tactic used to violate your 4th Amendment right, which protects you from an unreasonable search and detainment, simply refuse to open the door. Be prepared for the police to threaten you will all manner of retaliation including returning with a search warrant. If they could leave and return with a warrant, they would have arrived with the search warrant and kicked your door instead of knocking at your door. If the police do leave to obtain a search warrant, you will have plenty of time to rid your dwelling of any contraband before they return.
Other popular and well meaning lawyers and activists teach to open your door and step outside and immediately shut the door behind you when meeting the police on the porch. This method DOES NOT WORK for reasons discussed above. I have been retained by dozen of clients who used this method and are now in a big jam because they opened the door.
NEVER OPEN YOUR DOOR FOR THE KOPS! Make them kick it. If the police had a right to be in your house, they would be kicking, not knocking. You have the right to screen who comes in and out of your house which also applies to police officers. Citizens are under no obligation to allow police to enter their homes.
Watch this short video as Barry demonstrates how to deal with police when they come knocking. This clip was taken from Barry's NeverGetBusted DVD, Volume 2: NeverGetRaided. Although this tactic is still extremely effective, a new Supreme Court ruling allows police to kick in doors if they smell marijuana and hear what they think are persons destroying evidence inside the home. Read that story here.
Unlike the demonstration in this video, sometimes it's better to simply remain silent and not answer the door.