I have never seen anyone come up with a way to disable it. You may be stuck. The only other way is to fasten seatbelt behind you although that is kind of annoying and uncomfortable. Or by just the seatbelt fastener part and have a detached from the seatbelt itself and stick that into the slot.
2017 YMB ///M4 - August 16th ED -----> PCD/M School - October