I had always assumed that the ligature had been constructed that night, since there were shards from the paintbrush handle found outside the wine-cellar, or somewhere in the basement, suggesting the person who made it placed it against the wall and broke it with their foot?
I dont doubt that the ligature and paintbrush handle can be interpreted as an AE Device, but if you accept that: "John Ramsey himself said the perp was experienced in erotic asphyxiation", then why is an accident advanced as the probable cause, particularly if this is not the assailants first assault upon Jonbenet? From the prevalent analysis JonBenet was not only sexually experienced, e.g. her enlarged hymenal orifice; but was also schooled in EA, e.g. Lou Smit, Cyril Wecht, John Ramsey, LEA et al; All this at 6-years old!