Hi,
I thought it might be useful to post this YouTube video. I, and a few others I have seen have been RPing the concept that if you touch someone when they are tazed you would get a shock too which would be logical to assume with electricity, but clearly from this video that is not the case. I got an explanation from someone who said that the current actually flows between the prongs and not to earth, the high voltage pulses disrupting the nervous system and causing muscles to tense. This also means the suspect would not necessarily drop anything they were holding as you can see from the clenched fists in this video (and as poor Angel has now found out to her cost!).
http://www.youtube.com/watch?v=SCLXiqnwmpw&feature=related