I am an IT geek. When you connect to your isp, most have floating IP addresses and assign you one that is free when you connect to the internet (which will be your external IP address). Each house/computer does not have a unique IP address. Therefore VS would only know the ISP that accessed the account from the IP address and not the individual.
If VS wanted to track the individual they would need to get the ISP to provide that data, which they would not have the power to do (unless the had a court order).
Not to mention people access accounts from work, home, mobile, etc..... which all will have different IP addresses.
Basically, VS dont have the power to track users from ip addresses/location. They basically only have the account details used to create the account
If they are logging into both accounts from the same pc, then both accounts would share ip addresses. The ip would change between disconnecting at the house, but there would still be a pattern.
Admin in bigfooty can track which users have logged in using the same ip address, surely vs could do the same