When they recovered my motorcycle after being stolen, it had two big velcro patches where the plate was supposed to be.
Now that's actual edgenuity!I used a hole drill and opened a hole at the innermost edge of the two license plate elongated slots. I then took a ~1/2 inch long pan head slotted screw (see pic), and threaded on a washer and thin nut. I then slipped the round head of each screw through the hole I just drilled in each slot and moved it outward to the spot it needed to be when holding the license plate (around the center of each slot). Then while holding the end of the screw with a pair of vise grips, I tightened the nut against the washer. Then I placed the license plate on the remaining length of the screw, and held it down with two locking nuts screwed onto the now stationary screw. The plate sits about 1/8 inch off the rear fender due to the width of the first washer/nut, but I don't really notice. It seems pretty secure and tight.