Gray area or not, it's illegal what most servers are doing at the moment and that's clearly visible from the current version of EULA. It was said that they will find a better way for getting money from MC, but at the moment ranks are being illegal and Mojang is digging their own hole and falling into it. However, I don't remember that I agreed to EULA anywhere, and Mojang is aware of that, that's why they are forcing you to accept it when updating MC to 1.7.10. And because you never really agreed to it, you don't have to worry about it, only till you update to 1.7.10 ofc.