AFK'ing with Guthan's is good and safe. I remember getting 99 def at Bandits back in the day, afk'ing basically 20 hours a day, even over night. Good times.
Got banned today after 4-5 hours of botting over the past 5 days. It was a year old account that I just started playing on again. I guess it was probably flagged already since past botting - I did feel like I was getting a lot of randoms - but this is still absurd; something very native to the OSbot api must be detectable.