Perfectly stated.
I used to bot and play legit, averaging probably 20 hours a day played on my account for months straight. Never got a ban. Then I stopped playing and only botted, in 2 weeks I was banned. I think its because of what Anon said above, they were doing tons of updates during that time and since I was never online when the bot was down its easy for them to see who's botting or not.
Exactly it makes sense logically that this is their main detection part. Other detection might be seeing like your mouse movements and stuff like that but doing that for every player is insane so i don't think they really do that.
We always see threads AFTER an update and when OSBOT gets updated that they get banned it quite common sense