¿How do you determine a use of an illegal program?

Hello, with all respect, i write this question because i'm curious with how do you determine that and if you can tell which program.

In Jul 11 i was banned for being a bot when i was just open an another client (dualboxing) to follow my other character form another account to prevent an alliance gank, and i get surprised when i get banned, immediately i look in the forum, and what i see is that in the rules multiboxing, cant get you flagged.

The same day i opened a ban appel to explain my situation an get an answer, today the answer was "This case has been reviewed. This account was found to be quite clearly utilizing illegal programs within our realms."

Im not asking for a RE-review of the case, i just mentioning for make the big picture, I'm really curious why my other account dont get ban if i was using the same IP with the same PC, and if you are so kind to tell me what program was the cause of that ban, becouse i want to keep playing in this server and i dont want to get ban for that in the future.

Thank's for your attention and hope you have a great day.