Microsoft says Gmail is a virus

It seems that Microsoft has started flagging Gmail as a virus in their virus scanning software Windows Live OneCare.  Many people are reporting that every time they open Gmail, a warning is displayed telling the user they are infected with "BAT/BWG.A".

Now, either Gmail is a virus, or Microsoft is generating false positives.  Some affected by this "virus" say other anti-virus products do not pick up the infection -- to me, this is a bit suspicious.

So who should be responsible for fixing the problem?  Either Google can wait for Microsoft to update their virus definitions (I don't know how often that happens, or if this will be fixed when it does), or they can identify what is being flagged and change it right away to avoid annoyed users.  Another question I have is whether any sort of legal action can be taken if this continues for an extended period of time, and it turns out to be false?

One thing is certain, those who use Windows Live OneCare and Gmail are all worried they have a virus they can't get rid of.  Some might even get frustrated enough to either quit using Gmail or Windows Live OneCare depending on which one they think is to blame.

Update: 

"I would like to confirm that this was a false positive and let you know that we pushed a fixed signature to Windows Live OneCare users today.

We will investigate how this false positive happened and take steps to minimize the risks of additional incidents." -- Ziv Mador, response coordinator in the Microsoft Antimalware team.

[thanks Murrell]