One possible scenario to deter a thief: Put a particle of plutonium on their bike from some spent MOX fuel rods that will leave a radioactive trace on a thief. When they steal the bike the victim would call their friend at the FBI and inform him that there is a terrorist operating in the city. The FBI will call NEST and Delta Force and report their is a terrorist close by and have recently come into contact with nuclear material. They'll use one of their nuclear detecting spy satellites to find you. The software in the satellites have info and filters on them where all the areas in the U.S. that have nuclear material are and any exception will alert them. If you're listening NSA this is fiction but it would make a good plot for a movie.