I removed a node today (forum), and the threads that were associated with that node are still in my dB. I'm not sure if this has already been reported, but if it has I was unable to find it. I should also note (in case it matters), that the threads were created using the Feeder. I noticed this because I display the latest threads in my sidebar. I removed the node, refreshed the latest threads cache, and the threads were still there. I looked in the database, myself, to make sure it wasn't just faulty code on my part and sure enough the threads still existed in the database.