First of all, a normal traffic ticket is not an "arrest", you are issued a summons to appear in court to have your charge heard. Unless there is a DWI, drugs are discovered, some sort of obvious negligence resulting in death or any other serious crime is committed, you are written a summons and are free to go. If they take you to jail and book you, you will be fingerprinted, photgrahed and that will be come part of the permanent database inconsequential to the outcome.
"Steal your DNA?" That's very easy to do by anyone at basically anytime. Your lip print with saliva off of a glass, a cigarette butt with saliva on it, your hair falling out and captured, loose skin cells from clothing. Just a little strategy, a trick or two and they have you if they want you! What are you afraid of that they may do with it?
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