(CBS) — Northwestern University’s annual Colorado ski trip has sold out for the first time. But as WBBM’s Bob Roberts reports live, those who hope to use it as an excuse to “get high” legally are getting a warning.

The Northwestern Student Handbook says recreational drug use us prohibited except as expressly permitted by law. Colorado law says pot use is legal for adults but federal law says it is not and that is what counts with university administrators.

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An NU spokesman says its fear is that if permitted, the university could lose a range of federal funding, from Pell grants to research money, so pot use will be prohibited on the ski trip.

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The NU chapter of Students for a Sensible Drug Policy wants students to protest.