I play with EEG hacking in my spare time. I was shocked to find out that one of the commercial ones has NO protection circuitry in theirs, and after discussing with their engineer they simply recommended to me that I should unplug the laptop from the socket!

I brought this up with one of my engineers, and he said I was getting my knickers in a twist; the likelihood of dying from this truly would be a series of unfortunate events.

So: beware, even with the commercial units. Dissect them to be sure!