It looks like the camera (I'm assuming phone) was sitting on a table or something. If they were all high, they may well not have noticed. Doesn't require a master of gadgetry to do that. Of course, given what's gone on in the past, you'd think Ford would be more careful whenever phone were around, but I expect he thought this guy was a friend who wouldn't do that to him. That, and I'm pretty sure Kathy and Sandro aren't the brightest bunnies in the forest.The drug dealer would have to be a master of gadgetry to have filmed that without any of the 3 others noticing.
Or this sums it up perfectly:
I don't think it would be too difficult to surreptitiously record three drunk crackhead morons in a dim basement.