If I may speak here...

Personally, I do not participate in chat. I am happily collared, and find most chat merely makes me uncomfortable, so I avoid it. However, I can speak as to my general experience and rules on the internet.

I am a submissive. I am not YOUR submissive. I will treat Y/you (this is a general you, not a pointed post at one person) with as much respect as I feel you deserve from me. If you treat me with no respect and like I should simply bow down and kiss your shoes, you will get nothing but disdain for me.

My Master has trained me to be polite and respectful, but I do not bow to any commands but his. I will respect the Dom/mes that I meet, but will not perform any tasks they ask of me, as it is not their place. So, any attempt to "punish me" for my mouth will be pointless. You could consider that hiding behind my collar, I suppose, but for me it is a matter of following my Master's rules. I am submissive and slave to him and none other.

I believe the difference between the real community and the online community is that, yes, there is less policing by doms of their subs' behavior. In a real community environment, I would be two steps behind my Master at all times, and any misbehavior on my part would merit punishment. In the online community, he looks over my shoulder from time to time, but doesn't feel the need to make sure I am being on perfect behavior. Many of the subs on this site probably have little or no supervision from their Masters/Mistresses/PYL. Thus, they can act how they wish to act, with no consequences. However, I don't think it is the place of the other Dom/mes to be punishing the behavior of subs not their own, especially with no explicit permission from the sub's Dom/me. I can tell you personally that my Master would kick the ass of any Master/Mistress/etc who tried to punish me without his permission, and I have been told not to obey any orders that he hasn't approved.

A responsibility? Yes. Each submissive is responsible for his or her own actions. The Dom/mes are in some part responsible for the actions of their submissive(s). Responsible for the actions of other submissives they don't know or have trained? I think not.