My apologies for breaking it into two different posts. A person utilizing an ITIN does pay Social Security tax to the IRS, which in turn remits to the SSA. These funds are set aside for Congressional plundering. This was the reason that the ITIN is structured as 9XX-XX-7XXX. State and municipal payroll taxes still vary in the requirements, but I have never heard of them aggressively pursuing a person with the intent of refunding monies. I am most familiar with Texas (duh!), and they assign a different sales tax ID# now for businesses. Because it used to be the proprietors SSN, and had to be prominently displayed. That did not work out too well, to say the least.
The earnings suspense file is growing by $50 billion a year.