Originally Posted by
Flight
That's a difficult question to answer and impossible to answer accurately. There's not been any evidence of banning due to 3rd party clients unless that player is flagged for something else first. I can't tell you how many accounts I've had banned via using the official client. In fact they probably outweigh the number I've had banned while using SMART, as odd as that sounds. I've noticed the only aspect that solidly leads to a ban is in-game actions that simply don't make sense. Like trying to interact with an object/NPC/Item/Player that's out of reach, multiple times.
I also just recently received a minor ban on an ironman account while developing a smelting script. Without adding failsafes, the script tried to smelt steel bars while only having iron ores, and continued this for no more than a minute before I caught it. Even after correcting the issue, hours later the account was banned. So in my opinion, it's the in-game behavior that truly impacts accounts being flagged, maybe after that aspects such as 3rd party clients are detected. Who knows really...