It does not remove the ability of law enforcement to serve a search warrant and carry your computers out the door, nor does it remove the ability of a judge to plant you in a jail cell until you cough up the passwords. What it does do in create an incentive for anyone who does serve a search warrant upon you to look very, very closely at the contents of the drive once you do provide the password -- if you thought the inconvenience of full-disk encryption was this important then they are likely to think that they will find some child porn or tax evasion documents buried in there somewhere.