With the appearance of the final version of FaceTime in the App Store -at the price of 0,79 euros, yes- it is sure that the use is extended much more, so let's see a trick that may be interesting for your FaceTime.
To automatically answer calls in FaceTime for Mac you have to put this command in Terminal:
defaults write com.apple.FaceTime AutoAcceptInvitesFrom -array-add
Where identifier can be a phone number or an email, since FaceTime works with both. The good thing is that doing so improves privacy, since we filter the ones we want.
Thanks to one that I know - he does not like to be named - for passing me on Twitter.
How to put this command in terminal could be more specific to do it since it could work as a security camera
Thank you
rgz