When similar measure was implemented for printers, it was not only not opt-in but also a secret for quite a while: https://en.wikipedia.org/wiki/Machine_Identif

When similar measure was implemented for printers, it was not only not opt-in but also a secret for quite a while: https://en.wikipedia.org/wiki/Machine_Identification_Code https://en.wikipedia.org/wiki/Machine_Identification_Code The possibility of this being opt-in is so unlikely it probably not worth discussing.