In your home state, you have a medical marijuana card. It helps you with pain, so you don't think of it any differently than any other medication. Upon deciding to take a trip, you pack it in your suitcase and head out.
One thing you have to remember if you travel is that laws change from place to place. In Port Canaveral, thousands of people returned home after a trip on a party ship. Unfortunately, some people missed that trip because they had drugs in their possession. According to the story, a DJ and around 24 others were arrested for possessing marijuana and other drugs. Now, they face charges. Federal, state and local law enforcement took part in efforts to prevent drugs from making their way onto the ship during embarkation.
The Holy Ship! Festival held on the cruise ship was supposed to be a fun time away, but several people were stopped from boarding because of possessing marijuana. Despite the fact that they had medical marijuana cards from California, those cards were not accepted in Florida. Florida law does not permit medical marijuana from other states to cross into its borders.
Florida is still trying to work out its medical marijuana laws, so some people may have been caught off-guard by not being able to possess what they can legally have in California.
If you get caught in a situation like this, it's advisable to defend yourself carefully. You don't deserve to face charges when you legally obtained a substance, but with state laws that vary, you could end up facing various charges that you need to fight.
Source: Florida Today, "Party ship hits the high seas as prosecutors warn about pot laws," J.D. Gallop and Tyler Vazquez, Jan. 10, 2018