I'm a medical patient in California. As I understand it, I'm allowed to visit another patient in my state and obtain seeds, clones, buds, and extracts. Ordering these items through the mail however bypasses state law and follows federal laws which doesnt protect me.
However if a friend in another country who didnt know U.S. laws were to gift me seeds and ship them to me as a surprise present, I could not be found liable. Still, it's considered contraband and customs has the authority to destroy the seeds if they discover the contraband. The current policy of customs is not to go after the recipient in most cases. They will only mail you a letter informing you that your package has been confiscated or destroyed. It's possible if you have a large quantity they might pursue further action, but to date I haven't heard of that occurring.