Computer (hardware) ID:
Upon the first install, a Hardware ID (HWID) will be generated from your computer, based on an algorithm applied to several identifiers in your system.
This could be everything from 10 devices to just your MAC address.
The MAC address alone seems highly unlikely, because a) not everyone has a NIC, and b) that would mean that "tolerance" is not possible.
I connect by cable modem, and the company I go through, the IP automatically changes evey few days, no matter if you stay constantly connected, or reboot.
You change operating system, add new hardware, remove hardware, that to also changes your computer (hardware) ID.
Anyway, my understanding is: Only one account per household, address and/or computer to a casino.??
My roommate has own computer, but we use same connection through a server here at home. I contacted the casino I already had an account with, told them roommate wanted to open one, they told me what to do, I (we) done it, and no problem at all with either account.
All players have to do is take time to check into the Rules of the casino, then contact them about anything they are not sure of.
And do as they instruct you.