I know quite a few people who play the game completely on someone else's bill, be it their parents or someone else. Don't tell me you don't know of some kid when you were going through school who seemed to get everything handed to them, from clothes to even cars, not having to do a lick of work for it? I've no doubt that if something like Blizzard selling gold were to happen, those sorts of people would become very obvious, -very- fast. I don't play any, but I'm pretty sure you can pinpoint the people who have things handed to them pretty fast on any of the pay for premium 'Korean' style mmo's out there.

Or, on the opposite side of things, are people who work and have bills, but have no problem with using a lot of their money on 'play' items...I used to play the online strategy game 'Evony Online', and unless you got in on a brand new server within a week or two of it starting you had little hope of competing (at least back when I played) against anyone who had a head start on you, regardless of the bit of time where you are 'safe' from attacks from other cities. The biggest 'guilds' were usually run by people who had no problem throwing money at the game to get items, which they then used to dominate the server. People would flock to the 'popular' guilds either because they didn't want to be attacked by those groups, or simply from the whole moth to flame situation. I imagine RO and other games of a similar bent see this, too.

I don't have much experience with any other games that offer things in exchange for real money, but I pointedly avoid them, -for that reason-. There's the sense that you're not 'special' enough to access certain content, that you really can't compete with those who can pay for things, regardless of how much the game developers will jump up and down claiming that you can. (Like the D&D online game where you can play for free...but you are restricted in class and can only have x amount of gold on you at a time. Sure, you can still compete with the guy with the premium account who can carry enough gold to buy that high priced awesome item on the auction house, serious!) I don't play those games, and I wouldn't play WoW if it even came close to it, either. Minipets are one thing, premium features or gold is another.