I'm not sure about client detection, but i think it is possible for Jagex to moniter accounts logging in from an unknown client since really there isn't that many. if we were to assume that Jagex could select what clients to moniter then they could easily detect ours as it is just a few packet changes?(assumption idk) and really it doesn't take that much power to do it.
but i do think having a really good script plays a big role since i use some scripts 16hr/day 6day/week
actualy ignore this