I don't understand how revealing a password to a PC's superuser is a security flaw. Did you know that Windows Vista and Windows 7 offer the same "flaw" to 56K dial-up users as well? It's true: It's been there, in the OS, for nigh on four years now.
The wisdom of doing so is clearly up for debate, but the feature neither adds nor compromises a properly managed PC's or network's security. Anyone with administrator rights on a wirelessly-connected PC can learn its connection keys trivially, whether through
a built-in tool such as this feature or a third-party tool found by a trivial Web search.
It is the network administrator's responsibility to regulate which systems can access his network, when, and how, but that responsibility does not extend to those systems' users. It's the system administrators of each system who are responsible for regulating
which users can access those systems and regulating which networks their users can connect to. In most companies, those two responsibilities are carried by the same person or the same department, but they are separate responsibilities. In homes, those responsibilities
should be carried by the heads of household or a single trusted family member, but through user ignorance the responsibility of system administration, separate from network administration, often falls to the primary users instead.
When you allow a system to connect to your network, wirelessly or otherwise, you must trust that the system's administrator will not compromise the security of your network by disclosing any network connection credentials. The only way you can do this,
if you don't trust that system's users, is to prevent any of them from being that system's administrators.
In a home network scenario where you're that network's administrator, the best way is exactly according to the post accepted as the answer: Become the system's administrator, and make all its other users limited account users.
And occasionally change the wireless network's password, as should be done with any password.
Edit:
A reasonably secure alternative, in the case of outside contractors or consultants needing access to your network from their own wireless-enabled laptops, is to create a separate wireless network connected via ethernet to your main network, for which a separate
wireless key is required for access. Just monitor this separate wireless segment for abuse, and you can take action to curb or remove potential abuse by the outsiders without affecting the operation of your internal network, and without anyone outside needing
to learn your inside's wireless credentials.
Windows Genuine Advantage disadvantaged my genuine Windows. Posted from genuine Ubuntu.