I don't mind such a system but the one problem I currently see is the ability for publishers/developers to ban without due cause and get away with that by implementing terms that state that the company may ban you for any reason, at any time, and do not have to give any reason what-so-ever. Steam already have such terms, for example (see below).
I don't like such terms simply because of the lack of transparency. I don't like the idea of being able to have my account and all related access terminated at the drop of a hat, without any sufficient proof given. Not only this, but because services like Steam consider their products "services" and not "goods", I don't believe there's much I can actually do about it.
Whilst companies will try to defend themselves by claiming to never unjustly ban someone, that's not very reassuring given the fact that the possibility of them doing it is still very much there, and it can be quite difficult to prove you were hacked or lost access to your account unwittingly.
It's unlikely any company that wants to remain in good-standing with it's consumers would actually resort to these tactics on a huge basis, but the risk is there and there's been cases where some companies have already been accused of doing this (some - like Microsoft - were even caught doing it).
http://store.steampowered.com/subscriber_agreement/
5. ONLINE CONDUCT, CHEATING AND ILLEGAL BEHAVIOR
Valve may terminate your Account or a particular Subscription for any conduct or activity that Valve believes is illegal, constitutes a Cheat, or which otherwise negatively affects the enjoyment of Steam by other Subscribers. You acknowledge that Valve is not required to provide you notice before terminating your Subscriptions(s) and/or Account, but it may choose to do so.
Note the wording in the second bold line. It's a common term that allows the company to define what "illegal" is in their eyes. Whilst in some countries you may be able to argue certain claims, the fact remains they can largely do whatever they like.
13. TERM AND TERMINATION
Either you or Valve has the right to terminate or cancel your Account or a particular Subscription at any time. You understand and agree that the cancellation of your Account or a particular Subscription is your sole right and remedy with respect to any dispute with Valve.
Note the wording on this, too: Either you
or Valve can terminate or cancel your subscription
at any time.
13C. Termination by Valve.
1. In the case of a recurring payment Subscription (e.g., a monthly subscription), in the event that Valve terminates or cancels your Account or a particular Subscription for convenience, Valve may, but is not obligated to, provide a prorated refund of any prepaid Subscription fees paid to Valve.
2. In the case of a one-time purchase of a product license (e.g., purchase of a single game) from Valve, Valve may choose to terminate or cancel your Subscription in its entirety or may terminate or cancel only a portion of the Subscription (e.g., access to the software via Steam) and Valve may, but is not obligated to, provide access (for a limited period of time) to the download of a stand-alone version of the software and content associated with such one-time purchase.
Lots of junk text here but the second point is noteworthy and states simply that Valve can terminate your subscription of a one-time purchase (such as a single game) entirely or partially, at their discretion. They also may provide access to a stand-alone version, but are not obligated to do so.
"You either die a lurker, or you live long enough to see yourself become a troll."