Their test method is based on hardware information, such as your computer's hard disk, CPU, network card are built in a unique information, like a human fingerprints (but Taobao specifically based on which hardware information to verify the answer I can not determine). So you'll be able to start that situation, and you'll be able to block all of the numbers on that computer.
So you can't use the same computer for both normal and abnormal numbers. (If your computer is connected to the router, the normal and abnormal best to distinguish between)
Refer to now a lot of software anti-piracy technology, are on a computer to generate machine code after verification, change to other computers on the installation of the invalid. The principle is pretty much the same.
Supplement:
You said the example of the situation, I think there are only two possibilities:
1. two computers can be almost the same time, so that the IP address is the same
2. two computers in the same router environment has not been updated
So the insurance method is to use the new computer to dial out directly to the broadband, but router. That way there's no problem.
Additionally I am confused that your IP just change a little bit on the line, he Taobao can not because you use the 253 IP all blacklisted it, who knows that IP you do not need to be distributed to who.
Checking on the matter of Internet accounts, unless they are privately cooperating with the telecom, otherwise how can they know. It seems that when signing the agreement, the telecom can't leak the customer's information except in the public security department's investigation and evidence collection
This is the first time that the telecom has signed a contract with the government to provide information about its customers.