Might wanna take the time to adjust your throttle cable play while you are at it. Just to be sure.
I once a Ninja 250 and I would use the bar end as a cruise control when I knew I would be on the highway for a while. Before I left, I would simply tighten the bar end enough so that it would interfere with the throttle on purpose. Knowing that I did this, I had to conciously push the throttle closed when I got into stop-n-go traffic. But if I ever got into a situation where I would be in town for a while, I would simply loosen the bar end.
It wasn't the safest thing to do. But it was cheaper than buying a throttle lock.
Speaking of cruise control, some people also just use an O-ring from a John Deere tractor or a Caterpillar and roll it into place:
