Not really possible to do it quickly sometimes.
If an SOS shard dropped under my name, I'd know immediately whether I needed it or not. Likewise if a caster necklace shard drops, I know automatically that I don't want it and neither does anyone else.
If a more obscure shard drops (but one that one of my characters might use - say the Moron Belt), I need to check my shard list.
I don't have a zerging problem.
I'm zerging. That's YOUR problem.
I have seen this several times, but it was always just some caster goofing around drawing their aggro and getting them to teleport up there for fun...
I dunno if this was suggested or not, but there's a possibility that this might have happened:
Caster casts an AOE spell on mobs and runs through inn then portal to end...
Or,
Caster casts a DoT on mob and runs through inn then portal to end.
Since the Inn is safe as it's outside the map area and they can't teleport to it, but if you're back on the end bit, same map, and hence possibly teleporting up to meet you. Although the likelihood will then be an AoE causing the issue.
J1NG
Thelanis: Yijing (*Completionist* TR 20 Aasimar Scourge Monk Level 20 / Epic Level 10)
Thelanis: Pocket-Monks: Sightblur, Peashoote, Jigglypath, Jedinja.
Invisible Fences, unkillable Target Practice Dummy's, Shared Bank's, Pale Lavender Ioun Stones, the dimensional barrier between Eberron and Shavarath, I've broken them all...
Seen this too, but never when it wasn't on purpose. Mostly seen it done by earth savant sorcs.