an o-ring between the bar end weight and the grip. This achieves the same thing as what Chy wrote, " or just loosen the bolts securing the control to the handlebar and slide it outward against the end cap.", i.e., both methods add friction to the throttle grip, allowing it to remain in a fixed position. Place a bit of tape on the rubber o-ring overlapping the tape to form a tab of sorts. That tab can be used to remove the o-ring.
P.S.: I don't override dead man devices.
