Originally Posted by law dawg

It is not a roving checkpoint. It's a roving vehicle stop. I can't make that more clear. A roving vehicle stop requires reasonable suspicion to make. A roving checkpoint is a non-permanent checkpoint that is put up on occasion but that operates in all other aspects like a checkpoint. IOW, no cause is required to make a vehicle stop. I've worked both permanent and temporary checkpoints. I've also done traffic stops. They are markedly different.

A cop making a traffic stop generally does so with PC to believe a crime has been committed - a traffic violation or similar. As the USBP doesn't enforce those laws they are making, in effect, a forced detention (as in Terry Stop). That requires reasonable suspicion.