As most people have said, they most likely don't do IP bans anymore. Even if they did, it's as simple as resetting your modem to assign yourself a new IP. I know they used to do them years and years ago, but I think more people must have had static rather than dynamic IPs back then.
Also, to anybody wondering about having other accounts banned for offences committed on linked accounts:
They won't ban your other accounts unless they have some type of tie to your other accounts. These ties usually include but are not limited to: advertising a clan chat your main owns, giving your main gold, supplying accounts with botting gear from a main, etc. It's all pretty obvious stuff, so as long as you're careful not to link two accounts together while one is doing something illegal, you should be fine.