I think allowing people who want to come here to work in restaurants or wherever can be structured in ways that are not automatically exploitive. Making them legal via work permits could prevent that - they would be subject to the same minimum wage and worker protection laws as anyone else. My grandfather came over from Sicily. He was poor. He drove a truck delivering bananas to grocery stores. My grandmother took in washing. One of their great grandchildren is a now a law school prof, their great great children are attending Boston Univ and the Univ of Chicago. Yes, I know there is a different economic situation today, but there are still ways to offer migrants a chance for better lives here.