India, May 21 -- The US Transportation Security Administration (TSA) has quietly updated its guidelines to permit medical marijuana in both carry-on and checked bags, a shift that arrives weeks after the federal government reclassified cannabis as a less dangerous drug, and one that is already raising questions about what travellers can actually expect at the airport.

The TSA's website was updated on April 27, adding medical marijuana to its list of permitted items with the notation "special instructions." The change followed an order signed by Acting US Attorney General Todd Blanche on April 23, reclassifying state-licensed medical marijuana from a Schedule I substance, drugs considered to have no accepted medical use and high abuse pot...