I'm with kamieniarz here;
Only tool I've used for an account is kBot; No other accounts on the IP, and I got a capacha this morning (No botting for a week also, Lol), so kBot is in-fact detectable, although I have been using it for 4~ months without issues.
Being more and more people having capacha's with kBot; It's kind of sure bet kBot is detectable, exp with BP announcing on their forums they're clamping down on bot users.
Although: It's also possible someone reported the people who got the capacha, and BP manually checked, but with the volume of people complaining recently, I'd imagine it isn't that. exp with me; myself not botting for a week (Just logging in for bonus, and send sep to ship) on this account
regards
Tw
Edit: May be worth noting my prem ran out 2 days ago also (Lol)