The last one didn't even happen on US soil but at Vancouver airport; there are now more than 600 US customs agents stationed in multiple airports around the world:
Dublin and Shannon in Ireland; Aruba; Freeport and Nassau in The Bahamas; Bermuda;
Abu Dhabi, United Arab Emirates; and Calgary, Toronto, Edmonton, Halifax, Montreal,
Ottawa, Vancouver, and Winnipeg in Canada.
I Had My Electronics Seized by U.S. Customs and Border Protection: https://news.ycombinator.com/item?id=13453189
A US-born NASA scientist was detained at the border until he unlocked his phone: https://news.ycombinator.com/item?id=13629593
US Customs block Canadian man after reading his Scruff profile: https://news.ycombinator.com/item?id=13702981
The last one didn't even happen on US soil but at Vancouver airport; there are now more than 600 US customs agents stationed in multiple airports around the world: