Usually, it is quite easy to detect when people attempt to return using new accounts. The software allows mods to see the public IP addresses used by every account to log in and make actions. By collecting and comparing addresses, we can prove that accounts are connected to each other. You can see your own IP address by typing 'what is my ip' into Google.
https://en.wikipedia.org/wiki/IP_address
And yes, people try this all the time -- but we've been around the block a few times and we get a sense of when things are not as they should be.
