回複：xiaobaitu,我聽說規則變了，以前美國人去這些地兒不要護照

For foreigners, there is no change.
You can use I-94 to get in, same as Canada/Mexico travel. (with a few limitation, of course)
The change only applies to US citizen & PRs. They used to be able to travel without passport. Not after 2007.
However, foreigners always need to travel with passport.