False alarms come with all modern anti-virus programs, which are looking not just for signatures, but for viral behavior. Lots of legitimate programs do this, so we get some false alarms. It's just that SOME of us get our false alarms for free and some pay for the privilege.
And if you think about it, would you rather have your anti-virus cry wolf once in awhile when there's no wolf, or miss a hungry wolf coming for a nice visit?