"Too many agents think not working for any government means being beyond judgment. There are some rules that no one is above."
In the early days of modern intelligence work, agents who acted outside of organizations weren't referred as freelance. Depending on who you asked, they were alternately known as independents, soldiers of fortune, or just plain mercenaries. All of these terms pretty much fit the bill.
Faction agents stood for something. They did the work because they believed in an organization or a country or at least a cause of some sort. Independents were in it purely for the money. Most would do just about anything for the right price. Morality wasn't supposed to be their concern. This unfortunately resulted in most agents choosing to work alone. If your partner was only concerned with the payoff, there was little incentive for them to allow a partner to survive to collect half. This prevented independent agents for taking on jobs of the complexity and depth we see today. Even more unfortunate was the speed with which many independents would betray their clients, should the target offer a larger reward.
Eventually things changed. Nobody knows who first used the term "freelance" or who started circulating early versions of the code. But for at least the last half century, two rules have been agreed on by the majority of the freelance community. First, betrayal of one's client is unacceptable. Agents are free to terminate contracts with their clients, but the client should be informed immediately and under no circumstances should a client become the target. Second, while working under employ of the same client for the same purpose, agents are, for all purposes, a team, and betrayal of teammates is unacceptable. In most statements, this statement is left purposefully vague, but there is little confusion in the intelligence community. Even the greenest agent knows what it means to betray a teammate, whether it's direct violence, purposefully blowing their cover, or knowingly leaving them behind, as almost occurred during Operation Arctic Wolf.
Most view the code as a very, very strong guideline, but agree that there are situations in which it is too limiting. And while there are no official sanctions, violation of the Freelancer's Code (without very good cause) can have repercussions. Betraying the first part can result in anything from blacklisting among potential clients to finding that one's identity has suddenly become public, as happened with freelancer Kwaaku Ngwazi. On the other hand, open betrayal of one's team is more likely to lead to a bullet in the back of the head than anything else.