I have an active system setup in a local venue. Tonight, - a couple of the artists reported being "shocked" by the vocal mics (beta 58's). I've had the same setup in the same location for the last 6 months and today was the first time that anybody ever reported any issue.
I have the console (Mackie VLZ 24-4) ground lifted, as are my rack, the speakers, and monitors (to eliminate hum).
The guitar amps were plugged directly into a 4 outlet surge box, - which was plugged directly into the wall (grounded)