the way i see it is this: i intend to join a heavily focused pvp guild for competitive structured pvp
but from my exp with GvG guilds in GW1 they never want to run stuff in pve
i personally cant do the exact same thing over and over and over again without driving myself insane. i cant do bouts of pvp for more than a few hours without jepodizing the lives of fellow human beings
with that in mind id want to also join a guild that did explorable mode dungeons, that way when im burnt out from pvp for the day i hop over and kill stuff
and if my gf decides she wants to play id be in her guild too so i can spend time with her
the solution? get rid of the indicator in the guild interface that says "shit, this guy's online but they are repping another guild" with that gone everything works out since even IF they have that rule you just hop over to another guild, you appear as "offline" and the only way they'll know is by physically seeing you in the world, which if you hop to another server decrease detection chances by a large factor
TL;DR: come next beta event we need to storm the anet forums asking them to get rid of the indicator in the guild interface showign someone is online but repping another guild, or give us an option to become invisible to that feature
(no im not trying to plug myself for guild advertisements, i just wanted to lay out the context)