police aren't crime prevention, that's silly. We're not in minority report yet. Police catch people who have already committed a crime and, in some cases, are still in the act of a crime. If police do a single thing to a person who hasn't yet committed a crime, the police are doing something wrong (and are potentially themselves committing a crime). Boarder patrol, on the other hand, has as their entire purpose...patrolling the boarder. If someone is in Mexico still, then boarder patrol can (and should) do nothing to them. If they have crossed, then only then is being apprehended an option. Since there are currently lots of people crossing the boarder, we're not in a situation where boarder crossings are eliminated and the agents are just there to continue preventing new crossings. What you're saying doesn't make any sense, and your examples are just making it worse.