If I'm scanned while on foot, will running serpentine help me?

Depends who's scanning you. If there's a ship hovering above, maybe not. If the scanner has eyes on you, they'll have an easy time. But if you hide behind things, if you're not getting seen, then it's about hardening the gear you have, etc… maybe they can scan you, see your name, but they can't tell if you've got a criminal record or a weapon. There are ways to get around getting scanned.