Your argument is off base. Criminals are supposed to make restitution to a victim who suffered a loss. Here if an illegal does not use govt. services, no one has suffered a loss. The employer gains, the illegal gains, the govt. even gains via more taxes on a higher profit.
Further, even if an illegal uses govt. services, it will be a stretch to charge an employer. It would be like a citizen works at a 7-11, takes his paycheck to buy a gun, shoots someone and asking the 7-11 to make restitution.
So I find your restitution comment to be without merit.
We are talking about MONETARY restitution for a MONETARY crime. So your 7-11 strawman is garbage.
"Here if an illegal does not use govt. services, no one has suffered a loss."
This is not true. All the other employees that suffered a depressed wage are victims of the employer's action. All the people that paid higher auto-insurance because illegals didn't are victims. All the people that paid higher health-care costs because illegals used private hospital emergency rooms without paying are victims.
There are a myriad of ways that these employers have shifted a monetary burden onto society at large, not just government-provided services.