A respectable Vancouver psychotherapist who took a few rides on the Technicolor express back in the 1960s has been orbidden from entering the United States after a border guard googled him and turned up some trippy writing the therapist published in 2001. Andrew Feldmar, was accustomed to traveling to the U.S. five or six times a year to visit his children...
"Persons with AIDS, tuberculosis, infectious diseases are inadmissible," Milne said. "Anyone who is determined to be a drug abuser or user is inadmissible. A crime involving moral turpitude is inadmissible and one of those areas is a violation of controlled substances."

You can be barred entry to the United States because U.S. Customs thinks you are immoral based on your writings on the Internet.

U.S. Customs brings the culture war to the border.