Because it's so nice to be able to pick up the illegal alien day laborer at some lumberyard and pay him cash off the books and not have to worry about OSHA or workmen's comp or health insurance or basic safety equipment or safety training videos etc. There's the attraction to these heartless people who hire the illegals: they're as disposable as a used paper towel.
Pick them up and throw there azz out of the country. Get the employer and send him with the deportee. Or better yet drop the illegal in his home country and the employer off mid ocean with a farewell rock.
The takeaway is; dont hire illegals, it may end up killing you.