For a while there, when built-in webcams weren't quite as common, my employer would either remove the camera completely or, if that wasn't possible, they would smash the lens and sensor with a metal punch.
They eventually quit (now we can use Lync to do video calls, even) but a lot of people now put little sliding windows over their cameras (you can get them at conferences these days, branded with the Splunk logo or whoever's giving them out)
