"...Despite English fluency and U.S. work experience, despite U.S. diplomas and even advanced university degrees, these young people face dismal career prospects..."
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Uh, no. Unfortunately the majority of them do NOT go to college, as that is when they find out they do not have proper documentation. Even the Differed Action effort by Obama has not addressed this, as education is mostly a state level concern..

AND

As much as it may hurt Canadians to hear this, a California, or Texas raised Hispanic, does not view Canada as a great(ful) second choice. Even if their parents are deported from the USA, there is a large Hispanic culture where these kids were raised, the weather, etc. 

These are not tech workers from say India, these people do not have the same aspirations, and besides THEY ALREADY LIVE IN THE DEVELOPED WORLD-THE USA. A cold place with less material wealth is a downgrade.

You might as well be offering them Cambodia...so, uh, no Canada is not an option.