We are absolutely on the same page regarding the current situation, where people transfer off SoR. They shouldn't wear the tag. Personally, that's a rule I'd keep even if guilds could hold an infinite number of people. Why ArenaNet allowed for cross-server guilds in the first place is beyond me, it's like an open invitation for collusion and bad blood. I've booted people from guilds for spying (I caught my main tank and primary healer sitting on the enemy's ventrilo server, feeding information to our PVP team), and, while the stakes weren't as high for my 80 person unknown raid guild as they are for your thousands-strong enterprise, I do understand building and protecting the brand. It's the reason I spent an extra 15 minutes on the pirate jumping puzzle last night, using my handy-dandy flamethrower to light up the dark room at the end for a group of [SiN] that were working through it.
The question about Guesting (specifically Guesting, not transferring) came up on RaidCall last night, and the asker was told by several people that it wouldn't be allowed. That seemed unreasonable to me, so when I saw this thread, I thought I'd chime in and ask "why". It just didn't seem right to ask people to forego an intended social aspect of the game, when a simple "Please stand down while guesting" policy would suffice. Those people were, apparently, incorrect, so all's right with the world.
As an aside, if I ever wind up on the "evidence gathering" list, I hope you guys will just tell me what I've been accused of, so I can either make amends for whatever wrong I've caused, or be on my way. There's a lot less waste of both our time that way.