Directly from their FAQ:
"2. I am currently on a different IP from my usual one, but I want to log in to the site. Is this allowed?
Answer: You may log in from as many IPs as you like."
Also,you can only have 3 IP's connected to the tracker at the same time. If you have more than 3, your account could get banned.
I personally love their content, the quality is great! The invite system is closed so the only way to get in is by buying an account or getting one from a Giveaway.