Anti-trust laws don't apply to MS. Consumer protection laws don't apply to MS.
How far does this go?
From the sound of the feature being discussed, it does just what it is suppossed to do. Detect networked devices and allow them to run with minimal user response. It does that, and is therefore not defective. Its improper use may have side effects, but the manufacturer has no control over what you do with their product once yuo get it home. It sounds like what is happening here is finding fault with someone who made the windows for your house. It is not their fault that you left the windows open so the rain and the snow could come inside.
Also, the consumer laws that have been mentioned say the the merchant has the responsibility to the consumer. While this may be cutting hairs here, it would seem that the store has to inform us of the problems, not Microsoft.