Unless you are a small company.
There is this a family owned food distribution company. It started growing produce in an area where the only ones who did that job were ilegal inmigrants. As the time pass, the company started it own wholesale store and grew to 3 distribution centers and a store open to public. About 50% of the employees didn't have a legal status, they all were working with fake IDs and SS#. In 2009 Homeland Security came to do an audit, requested every employee's file and gave them 1 week to do it. 1 year later they came back with a hefty fine and the order of cleaning the files they found suspicious. The day after that HR met with the first 10 employees and requested copies of their documents. The next day only 50% of the workforce showed up to work.
That's how Obama mostly managed inmigration. While during Bush buses will come to the places to pick up employees, during Obama, there were investigations that resulted in fines and deportations.
Now, if you are a big employeer, I'm sure you were passing money to avoid been audited.
People without a legal status can't receive SS benefits, period. Thier kids may go to the public school, they may receive medical care (mortaly they can't be rejected for lack of of legal status) and that's about it. No food stams, no housing help, no medicaid, unemployement, no medicare and no retirement. Period. Most of them still go to work, pay rent, buy groceries, cars, cell phones, etc, and contribute to the economy. They know they are here ilegaly, and are willing to take the risk of been deported if caught.
America is breaking down by it's own people, specially those in power. There is no real free market when the corprations lobby to make the laws that benefit only them. There is no real capitalism, it's all corporatism and the greed of it's shareholders.