Working MORE than 168 hours per week?

SSA does not know how many hours you work, or that your new employer plans to have you work. Homeland security only knows if the name/SSN is authorized to work in the US.

Working TWO (or MORE) full-time day jobs 8am-5pm, on the same day, in states hundreds or thousands of miles apart?

Again, SSA does not know your work hours. They also do not know your work location. They only know your employer's address (which may not be the work location) and the employee's home address.

There are LOTS of different flags the SSA can see to identify duplicate FAKE SSNs.

SSA has a bunch of identity information, but know virtually nothing about your work. All the SSA gets related to your working is your W-2. They only know your wages (not your hourly rate, nor the number of hours worked). They don't know the days worked. They don't know where you actually perform your work.

All the information used in E-Verify is contained on the I-9. Name, address, birthdate, SSN, optional e-mail and phone, and potentially an additional identification number for green card holders and those on temporary work visas.

There are LOTS of different flags the SSA can see to identify duplicate FAKE SSNs.

There simply isn't. It's just a check that the name, SSN (or other ID number), and birthdate match.

--Peter