I don't think US vs. non-US has anything to do with it. It's an ambiguous phrase, whose meaning is usually resolved by context.

"It's expected to rain tomorrow" is a prediction, whereas "students are expected to behave themselves" is an expectation (with consequences, presumably).

In the former case we clearly aren't saying we want it to rain, just that we believe it's likely, whereas in the latter example we are clearly expressing that we do want students to behave.

It's ambiguous because "expect" has two different meanings:

> to consider probable or certain

> to consider reasonable, due, or necessary