Legal Answer
I'm not sure how many will care about it, but here's the more dry reason why gil selling is prohibited. I'll leave the question of "right" or "wrong" to others; I'm just stating facts about the "why." Of course, being that I am a player who has had to compete with the non-stop monopolizing and agressive tactics of many different gil sellers, I do not like them. But here's the deal (obviously, this is just US--other countries have their own laws and there are some international treaties, but I'm not as sure about them).
The whole thing starts with the US Constition in Article 1, Section 10. (
http://www.house.gov/Constitution/Constitution.html ) Any government has to start with a standard of legal currency. We are on a fiat system, which means each dollar bill is a "good-faith" note that you could exchange it at any time for whatever you need. Historically, banks used to issue their own currency, but that proved to be a disaster (check
http://www.factmonster.com/ipka/A0801059.html about that). So to protect the currency, the government regulates all aspects of *exchanges of money or money equivilents*. That includes things such as stocks, bonds, or futures which are as good as money and the backbone of our economy. (more dry reading at
http://cato.org/pubs/policy_report/cpr-19n2-1.html)
So what this means is if there is an exchange of money for money, does that make these gil sellers into banks? Are they federally insured? Do they make reporting to the responsible regulatory agencies? These are questions that we don't worry about because we are small, but companies like Sony will worry about because they are big.
And before anyone says "but I've never been arrested for..." let me remind you one simple reality: Most laws are not enforced until someone who has a responsibility to do something about it actually does something about it. Not only that, there is the problem of "equal protection" that has to be covered: you can't selectivly bring a lawsuit against one person and not another person--you have to do them ALL or NONE; otherwise you'll have a an easy case to defend. Just like with the new cases against people downloading music & movies or the signs that say "we procecute ALL shoplifters." It does not mean that it is completly legal because you keep getting away with it.
Now for the sour reality. This will more than likely NOT be acted upon by any federal agency in the near future until it becomes politcally advantagous to do so. Lets say, some kid steals money from the local charity to buy gil, and it gets on the news. The local people will pressure their public officials and...boom. Political foot ball. Happens alllll the time.
Hope...this helps. (oh dear...did I just post on the flameboard~??... /panic../cry..*nobody hurt me*)
