Drinking Age Strictly 21: No exceptions for tourists; always carry ID, as bars check rigorously. Open containers banned in vehicles/public in most states.
Declare All Food/Souvenirs: Must declare any items bought abroad (even snacks); undeclared agriculture like fruits risks $300–$1,000 fines.
Marijuana Illegal Federally: Legal in some states recreationally, but federal law trumps—avoid transport across states or near airports.
No Firearms/Weapons for Tourists: Illegal to carry guns; knives/pepper spray often restricted—check state laws.
Right Turn on Red: Allowed in most states unless signed otherwise; always yield to pedestrians.
Public Transport Tickets Mandatory: Buy/validate before boarding subways/buses; fines for fare evasion (e.g., NYC up to $100).
Drone Rules Strict: FAA registration needed; no-fly zones near airports/parks—permits required.
Social Media on Visa Forms: ESTA/VISA now mandates handles; inconsistencies can flag/deny entry.