Yes believe it or not it is possible. I just pulled mine off without having to remove the Safety mechanism. Hopefully you didn't tighten down the screw when it was first installed. If you did this might be quite difficult.
What I did was pull hard on the metal ring and spun it counter clockwise. At first it will rotate without much hassle. Once you get it out about half way, then it will get harder. Be patient and keep rotating it. It will seem like it isn't working, but it is. Once you have gotten it off, glue the bolt to the safety mechanism. There are small holes next to the bolt.

If it is too tight and you can't remove it, then that's fine. Find some time to go back to the Japanese Land Transportation Office (LTO). Break off the old one and request a new one. When they give you the new one use some super glue on the bolt where it will meet with the metal piece. Still install it loosely. Wait a day before removing it. That way the glue has time to cure. Once off you should glue the outerside as well. This way you have a stronger bond so you be able to remove it for years.

Before you jump to conclusions, I removed it for legit reasons. I was unable to replace my license plate lights because my plate is in the way (US to JDM plate adapter). Plus when I get my car painted, I'll have to remove it.