The vast majority of cases where this relevant (99+%) are identity theft, where you got the name / ssn /address through some mail or website or whatever and use

The vast majority of cases where this relevant (99+%) are identity theft, where you got the name / ssn /address through some mail or website or whatever and uses that to contract things on someone else's name. Also, finding differences in signature is much easier and much more advanced / developed than you would think. Even if you copy mine after seeing it or having a model, the places where you slow down your pen etc... Vary compared to me, and that can be detected. Is it possible with technology to make a perfect copy? Of course, but then you just move to the next steps of the case, and you already cleared out the majority of bogus cases. So having a fixed stable signature is a very good thing for you the user, and it always surprise me when I see people who think they played the system when they screw their own protection like parent.