What if it doesn't have a parking brake (like a motorcycle)? What if it doesn't have a locking ignition (like most military vehicles)? What if it's a Model T?

Illegal in Nevada too. Who knew?

NRS 484B.530  Unattended motor vehicle: Stopping engine, locking ignition and removing key.  The person driving or in charge of any motor vehicle, except a commercial vehicle loading or unloading goods shall not permit it to stand unattended without first stopping the engine, locking the ignition and removing the key.

(Added to NRS by 1969, 1502)—(Substituted in revision for NRS 484.445)

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Whoever said there's nothing more expensive than a cheap Mercedes never had a cheap Jaguar.

83 300D Turbo with manual conversion, early W126 vented front rotors and H4 headlights 400,xxx miles
08 Suzuki GSX-R600 M4 Slip-on 22,xxx miles
88 Jaguar XJS V12 94,xxx miles. Work in progress.