[Clint]

Yes it is i talked about this with some people at mpcforum.com ..... and sniffing packets from the server is illegal... and wpe pro can be used to DOS so yes thats illegal too...as far as i know memory editors are 100% legal because they modfity the memory but modiftying packets that are sent to the server i think is illegal.. i dont know about that one tho

[Prophet-]

Yes. It goes against the Terms of Useage so there it would be illegal.. Its a form of hacking, editing that which isnt yours.. The program itself isnt illegal, but filtering that sort of stuff with it is.