attacks in the falls church, virginia area and realized that guy goes where one of those happens. they put a tracker on his bumper and they re tracking him on a public roadway and they realize wait a minute, that guy just grabbed a girl and dragging her away. that s when he was convicted. there are lawful ways to do this without violating tailing him? tailing him or going to a judge almost any judge, even i would have granted a search warrant. on the basis of the information that they had about him. convicted sex offender in the neighborhood of prior victims, looking for another victim. almost any judge would grant the warrant. then you wouldn t have this issue. here s what the court said. they said the fact that the police used technology to follow the van s movements on public streets, that s the key, public streets, did not somehow invade his recognized privacy interest because the gps did not act as a substitute for unconstitutional police action. what does that mean?