if you are a long-time wow player, you may remember a bug in vanilla that allowed players to summon "multiple" pets at once. it was actually just the player spamming the pet items (companions weren't learned spells back then) over and over again, which made it look like there were many, many vanity pets out at the same time.
well apparently there was a similar version of this bug that came with patch patch 4.0.3. (i believe it's been fixed now with patch 4.0.3a.) it was a much more extreme version of what you could do in vanilla, mind you. to the point of crashing a server, possibly getting suspended and/or banned, etc.
my initial thought when i first heard about it was "lawl, i have 140+ pets... i wonder what it would look like to have them all out at once." i'm sure this is the reaction of many players. sounds like a neat/funny idea, let's try it! however, after some thinking, i've come to the conclusion that it's not as cool as it sounds.
not only is it disruptive of those around you and your server (i can't imagine the server having a fun time trying to handle all of your vanity pets being summoned and staying out at the same time), it's probably going to hurt the chances of developers actually willingly handing out an item or an ability that allows pet collectors to have more than one vanity pet out.
this time around it was a bug and yet it was abused to the point where GMs probably had to intervene. could you imagine if devs gave those same players an official ability of the same nature? think of the potential headache those players would cause. devs wouldn't be able to do much either, since it was something they willingly released, other than revoke the item/ability entirely or "nerf" it. and no one enjoys having things taken away from them, which is what they would essentially have to do.
with this type of behavior, i wouldn't blame blizzard if they chose the lesser of two evils and just came to the conclusion to NOT allow multiple vanity pets out at the same time. ever. it's just easier to manage in the long run. if i were placed in a similar situation, with a similar decision to make, i would probably choose the same route.
the only silver lining i can think of this post-patch occurrence is that it gives developers a chance to see how they can possibly create a future item/ability for summoning multiple vanity pets that won't or can't be abused. sometimes the only way to see if and how things work is to test it out first and find where the weaknesses lie. and then squish them like the bugs they are. :P
i know it's not just me that would enjoy having more than one vanity pet at any given time. yet with this type of exploitation, even if it was just a few people that did it, it makes it difficult to take the idea of having multiple pets out seriously. it could be ruining or drastically lowering our chances of a future item/ability. which is a damn shame.
so stay cool. stay classy. and remember that actions have consequences, however direct or indirect they may be.