Being allowed to engage in a privilege like navigating a motor vehicle on taxpayer roads does not mean that you leave your Constitutional rights at your driveway.
If you really think that your statement is adequate defense of unlawful searches like sobriety checkpoints, can you explain which other Constitutional Rights I'm also allowing to be suspended while driving? Maybe I can be beaten by police for having rosary beads hanging from my rearview by police that disagree with my Ron Paul 2008 bumper sticker? No freedom of religious expression or political free speech. No freedom from cruel and unusual punishment. No trial by jury of peers.
