[SEMW]

> It reminds me of how lawyers are happy to accept signatures by fax

The purpose of a lot of these sorts of requirements is not authentication. It's ensuring that if you do do it, you trigger the statutory requirement for some particular criminal offense. For example, a jurisdiction might have a crime of forgery which is substantially easier to prosecute than fraud (perhaps fraud would need the prosecution to prove intent to make financial gain, wheras forgery might be satisfied as soon as you can prove signature was forged -- hypothetical example, it will vary by jurisdiction and IANAL).

These sort of statues might have been written before computers or even faxes, and there might be caselaw to the effect that forging someone's signature and sending it by fax does satisfy its requirements of the offence, but none yet for just writing your name at the bottom of an email; things like that.

[devilbunny]

If you fax a fake signature, and you have any real or potential gain at all - boom, in the US it's no longer a simple state court case, you are now guilty of (federal) wire fraud.