Device warns you if you're boring or irritating

New Scientist report on a device that consists of a small camera attached to glasses, and connected to a handheld device. In theory, if the person you are talking to gets bored, the handheld device will vibrate. At present the software identifies actors emotions 90% of the time, & other’s emotions 64%. The article didn’t say whether the actors were acting, nor, for that matter, if people themselves had similar levels of difficulty interpreting “normal” emotions, as compared to those from actors.
The gadget is being designed to assist those on the autistic spectrum to identify when others are getting bored, though I’m not entirely sure how useful it really would be. The discussion accompanying the article covers many of the drawbacks.