There is a restaurant owner in Los Angeles whose strategically located parking lot is used by day laborers to look for jobs. Every morning, large trucks and vans would come by, specifically a couple of food preparation places and some landscaping businesses.
About a year ago, INS did a huge raid where they closed down several businesses that employed illegal immigrants. For a couple of weeks, the restaurant owner saw the crowd on his lot in the morning dwindle from hundreds to maybe a dozen.
Whenever you read about INS busts or see them on the news, you see the illegals carted off. The business owners get a slap on the wrist, or a small fine. You don't see them prosecuted or closed down. Because they have lawyers and connections.
Businesses that employ illegals are the newest "speakeasys". This is the new Prohibition. If you threaten to shut down the businesses and send the owners to jail, they won't be tempted to hire illegal workers.
Business owners say this will lead to higher prices. Which is true. It will also lead to more jobs for legal residents, at higher wages.
This is the question of the day -- would you be willing to pay higher prices for all consumer goods, if it would solve the problem of illegal immigration?