Guess I'm not eqemu oldschool enough to have seen this before.
This has nothing to do with GMs, though :P If a GM death touches you, your NAME! is shouted to the zone.
Did some searching, and this vztz reference is all I've found so far. I believe, as well as others, that it has to do with zoning in/out simultaneously with others.
http://webcache.googleusercontent.co...&ct=clnk&gl=us