Ever since the Thieves' Guild update a friend of mine crashes other players by travelling to them. It happened twice today and has happened on several other occassions. We were doing the pledge earlier, he travelled to me and *boop* the two dpses and myself crash immediately as he enters the loading screen after clicking "travel to player".
It seems to only occur when he travels to someone from outside a dungeon and into the dungeon, or when he travels from a dungeon into a city (like Stormhaven).
We tried to recreate the bug and made it happen first attempt:

It's only one toon he has that does it and I don't know if it's actually true, but we were joking around saying it was the Goblin costume he always wears that is to blame.
I've got to say the Thieves' Guild update sure did add a whole new variety of interesting bugs and exploits..
EDIT 1:
Turns out from zone to zone travelling to a player also makes someone crash.
EDIT 2:
Can confirm, wearing the Goblin costume and travelling to players causes crashes. I managed to crash 6 people at the same time by travelling to them while we were in a trial group.
I renamed the thread because of this. Hopefully it is fixed soon.
"Madness is a bitter mercy, perhaps, but a mercy nonetheless."
Fire and Ice