Should selling raid spots be allowed?

A guild called Invictus on Alextrasza has posted a sort of advertisement on their realm forum, offering to sell raiding gear to anyone willing to cough up enough gold. There are all sorts of responses, from "Hey, those prices are cheap!" to "This is cheating!" One poster said that players should go through these instances on their own, through teamwork and patience -- but a member of Invictus replied, quite eloquently, that players all over their realm are more than welcome to work their way through The Burning Crusade content on their own, Invictus isn't stopping that; rather they are just providing a service for people who might genuinely be in need.

Suppose, for instance, that your guild is in the middle of progressing through difficult content and a key player, such as a main tank, has to stop playing WoW due to real life difficulties. The next best tank you have in your guild is nowhere near as well-geared, and finding another outside person to fill such a crucial role could be difficult in the extreme. Invictus, they say, allows your whole guild to chip in and get your next best tank to pick up a couple pieces of gear from the highest raid instances in the game, thereby allowing him or her to catch up and start helping out much faster. It seems like a legitimate service to me.

Then again, this is clearly a different situation from some rogue who just wants some epic weapons so he can do tons of damage in PvP -- especially if he didn't earn this gold he's spending through legitimate means within the game itself. Is Invictus doing the right thing by opening the doors to all kinds of players? Should they be very careful in who they sell too? What's your opinion on the matter?

[Thanks, James!]