OK, but are they actually going to do it? Because if they do then they can be charged with interfering with a federal officer. It doesn't mater whether they do it or a regular citizen does it, they can be arrested and brought up on federal charges. Now maybe the local sheriff's office will stop any arrest, but good luck once that deputy leaves the county, the feds will just arrest you then. And then you're screwed. Now if every sheriff's office, state and city police would do the same thing then it would be the feds that were screwed.