Infraction: 8. All accounts must have a valid WoW profile.
Message to User:
Your WoW profile must be kept up to date. Please fix it.
I think the main problem would be people who have a large amount of abyss crystals, waiting for the price to go up. I can't imagine you could end up loosing much, worst case scenario a few people decide to list their Abyss and therefore the supply goes up and the price goes down. It will most likely stabalize after a while so there isn't much to loose apart from time.
I seriously doubt there are many people out there sitting on a large pile of abyss crystals waiting for the price to go up though. Common sense says the price on these items will continue to steadily drop over time as less gear is needed from entry level raids and more epics are disenchanted. Abyss Crystals are probably one of the worst "investments" you can make unless you are banking on a major change to enchanting recipes (and even then your opportunity to cash out would likely be a very limited window).
Of course, that doesn't mean you will be able to successfully increase the price for abyss crystals by buying out the AH and relisting. You might get a few sales at your increased price, but you are still fighting a slowly declining market and it would be nearly impossible to push the price upward by a measurable amount over a long period of time. Even over a short period of time it would likely be difficult to make money and there are many other markets with a more limited supply line that could be manipulated much easier I would think.
Another problem with this market is that the people who need these crystals the most (raiders looking to enchant best in slot items) usually have access to an ample supply of them via the guild bank. I am a big fan of selling goods to high end raiders, but abyss crystals do not seem like they would work especially well.