:jointsmile:

They think that even thought they are here illegally if they pay taxes the government won't round them up and send them back because they are paying taxes. The same reason Citibank has allowed them to get home loans if they register for a TIN to pay taxes and the IRS encourages them to get a federal tax payer number to pay taxes. The IRS doesn't care if they are legal or not as long as they pay taxes.