I did say 3000V was approximate for a human to feel a static event. And perhaps I should have put "to feel discomfort". I 'm sure some studies would probably go +/-1500V of the previous mentioned level. It depends on many variables such as body location of the discharge, humidity and your own sensitivity. But the reason the high voltage doesn't cause too much harm is that the current is miniscule. If I remember right, dragging your feet across the carpet then "zapping" someone is about 25,000V!!
The main idea for stating the levels was to point out that even though you cannot feel a static shock, does not mean it didn't happen.
Where is this all coming from you might ask? Myself, I have a technologist diploma and have been working as such in a electronics manufacturing environment for 6 years. Currently sitting as a Quality Analyst, ESD is a daily concern for me. I have had to sit through, I'm guessing, 10 hours of ESD specific training. (In those 10 hours, I'd never thought I would be talking about ESD outside of work though. sheesh!!). I too was shocked at those numbers, but there has been millions of dollars spent on research on this topic. Reason for that is there has been billions of dollars lost through ESD damage. I know this is not what the thread was started on, my apologies. I have very little experience when it comes to reptiles, but I do know ESD.
As for magnetic screwdrivers, I don't use them. I stick a hunk of tape or even a hunk of my gum to hold the screws if necessary. Why risk it if you don't have too?