Thomas Dalton wrote:
This
doesn't help ID the person (MAC tells you manufacturer, and
sometimes model, but that's all). But it does help for blocking...
It helps to confirm that two people are the same. While a checkuser
that shows that two accounts are being used by people with the same
ISP would at best be a "likely", a checkuser that shows two accounts
are being accessed via the same network card would be a definite match
(assuming the rest of the address rules out a public computer).
On today's OS it's easy to change the PC's MAC. No doubt vandals will
learn it fast.
Even worse, if we treat as one-MAC one-user, and block by it, a vandal
can vandalise with the mac of a legitimate user (one unlogged edition is
enough to disclose it), which will found themselves blocked and appear
as they were the vandal.