Alternatively, don't buy stolen property and then publicly announce that you've done so.
Once you've committed a crime though, definitely be smart about asserting your civil rights, using encryption, etc. And even if you haven't committed a crime, assert your civil rights and use encryption. But probably the #1 thing you can do to not get harassed by police is to obey the law.
Unfortunately, everyone is guilty of violating some law at some time. So it's best to ensure that your computer is not going to be testifying against you, especially when that is just one checkbox away.
You can always decrypt your drive when asked. But you can't encrypt it after the police take your computer.
Once you've committed a crime though, definitely be smart about asserting your civil rights, using encryption, etc. And even if you haven't committed a crime, assert your civil rights and use encryption. But probably the #1 thing you can do to not get harassed by police is to obey the law.