15% of 10,000,000 =/= 5,000,000

I frankly don't think CCP should moderate or otherwise interact with such activity in the first place.

Banking/loan systems are a clear example of emergent gameplay and as such should be fully operated by players, including the risks involved.

This is New Eden after all and part of that is both your freedom to do whatever you damn well please with any ISKies in your possession but also that you have to accept that it is not just outside of CCP's capabilities but also not their responsibility to take action when someone just takes off with the money you voluntarily transferred to him.

Also, relevant

You can't delete characters with a standing debt, and a percentage of all of your earnings will be put forward on the debt until it's paid off.

Hmm yes this would be a possibility for someone you couldn't trust. But CCP would be moderating it anyways.

They don't have a history of moderating things like that. At all.

Quite to the contrary, the link I provided states the chief executive of a player controlled bank, who has scammed players out of ~200bn ISK, would not have faced any repercussions from CCP, had he not proceeded to sell the ISK for real world currency.

CCP is generally known to stay out of player's ingame businesses. This includes lying, espionage, larceny, scams, con jobs and extortion as long as everything happens within the confines of the game.

You can even do things that, for pretty much any other company, would qualify as bannable harassment without punishment as long as you can prove that you're not going out of your way just to make someone's play time hell but that the harassment is a means to an end (like financial gain or seizing control over resources).

That's not to say that CCP is never giving players tools to protect themselves from scams et al. to some degree. Many risky actions you can make prompt clear warning messages alerting you of the potential danger of, for example, accepting a courier contract and depositing an escrow only to get ambushed and killed by the very same person who was issuing said contract in the first place so he can keep the escrow.

Beyond that though, you're pretty much responsible for your own well being as CCP will generally not intervene with ingame behavior as long as it doesn't leave the sandbox. If someone takes a hefty loan from you without intending to pay any of it back, that's your problem and you will have to account for the possibility. As harsh as it sounds.