As a follow-up to my last entry, I'll clarify the proper way to check for illegal workers. When somebody applies for a job, by law they would go to a certified ID verification service, similar to a drug-testing lab (which is common for employment these days). The employer itself would not do the ID check. Any employer that does not have a worker go to a certified station before work (or within a given time-limit) would be given stiff penalties.
The employee's Social Security Number (SSN) would be used to check their name, residence, and any current work locations. If there is an overlap with somebody else's work or tax record, a different name or address, or it's a non-existent SSN, then further investigation is done and the hiring is delayed until the investigation is finished.
Thus, even the best fake ID would produce suspicious overlaps in the tax records. Either the number is invalid or will produce conflicting information against the valid tax-payer with the stolen SSN number. Sure, there are ways to get around this, but the cost of working around such checks for an illegal migrant worker is generally prohibitive relative to their expected earnings.
As far as under-the-table work, larger rewards could be given for tips leading to arrests, including possible credits toward citizenship.
