the short answer is no.

the long answer is noooooooooooooooooooooo.

http://www.youtube.com/watch?v=Tim5nU3DwIE

Be aware that every computer you use gets tied to your account and you will start sharing mist with all other accounts that have used that computer. So, say you use the wifi at your local coffee shop to play SK and someone else has (or will) use that same hotspot to play SK, your two accounts will then start sharing mist unless you have a paid account.

in rare cases, if you have shared a computer with someone who gets themselves banned, it is possible that your account will be banned also. Usually, you can get those situations corrected by contacting OOO via their support system, but you have to convince them that you really aren't the player that has been banned. If you and a "friend" use the same set of computers regularly, it may be hard to convince OOO that you r friend isn't imaginary. Even if you don't get banned when the other player does, all the computers that you have used with get marked as "tainted" and you will not be able to create any new accounts on any of them without asking the GMs to make them untainted.

The vast majority of times, you won't have any problems, but sometimes it is best to not use a particular computer and if something does happen, you need to know why and what to do about it.

Yeah, if you control all the computers you have (and will) use your account on, you are safe.