The SSA is straining at the seams trying to keep you from finding that out. They actually can very easily track how many illegals are using your SSN. And, they are keeping the accounts straight for the most part. You have to realize in this day and age even the simplest of programs can find 'duplicate' entries. Why isn't the SSA doing it? The answer is: They are!; they just aren't telling you. This is a windfall, fiscally, to them because they get the contributions, but don't formally owe the false identities crap. All they have to do is to keep you unaware.
What the SSA doesn't realize (or does but has their head stuck in the sand) is that when Kommaner Kiddie Zer0 legalizes them they will be screaming their lungs out for SS and the contributions they made. Talk about instant bankruptcy....we are in for some real $hit in the next few months.