Many attempted to record with "normal looking" recorders and he was great at spotting them. The few of us with the Pulse Pen made it through the class inconspicuous and helped our fellow classmates study.
The livescribe pen I owned was a joke. It wouldn't record well at all if the lecture hall wasn't really small, and even then you end up with all the shuffling and whispering of people around you magnified much louder than the person lecturing.
Not to mention the model I had wanted you to wear these goofy headphones that have a mic in them, just to get the 'quality' of recording I described... a pen with headphones connected to it that you're wearing is not exactly 'inconspicuous'