Crystal Tower, first monster area (WEST) locks out all alliances with no one inside.

ISP: FIOS

http://img841.imageshack.us/img841/7500/a7xd.jpg

Fiber 75/75

Happened once.

Aria Cross

Miqo'te

Saragatanas

Blm/50

Area: CT, first monster area, elementals/dragons/diras. I was in Team B.

Alliance of 24 affected.

8:42 pm CST.

Steps:
Alliance runs west, all 24 members enter zone, zone lock out happens as normal. Alliance proceeds to take a tail whip from the south dragon under Team A's control. Wipes.
Everyone runs back, zone is still locked out and no one is inside. Even after the majority of people disband, still locked out.

So in summary, die to the west group of adds within 7 minutes after entering CT, get alliance locked out. See screenshot, barrier is up, no one is inside.