I don't know the function of the ring, but I've seen it on some bottom brackets and have always just left it on there. If you're so worried about it, your bike is probably under the UCI weight limit anyway.

If you really want to remove it, it's probably easier to get leverage (whether by using a flathead screwdriver as a lever to force it off, or by gripping and pulliing with some kind of locking pliers) once the bottom bracket is installed into a frame.