Do not use their SSN, you are ONLY allowed to use this for their tax information ...
For years and years I thought I was one of the few on earth who knew this ( my brother, an accountant, had provided a hard copy of the Federal rules governing this. It was one of his pet peeves. )

It wasn't until the banks and other institutions ( insurance carriers, etc. ) got spanked by the Feds when identity theft got huge media attention that things changed. ( some used the SS number as account numbers. )


Although I believe there are some exceptions I believe catch is correct. I would discuss your plan with a knowledgeable tax attorney as well as local council before attempting something like this.

(hence the military uses Serial Numbers)
They do? Did they get spanked too? In my day they used the SS number. ( I was in over 30 years ago. ) Any idea when that changed?