@ Parts, AWESOME, I'm green with envy now.
Once the use of bicycles was taxed. You had to ad a platelet on your bike, to show that you had paid the taxes of that year. Some people got their name hammered in the platelet, because they were stolen quite a lot. Others did not attach it to their bike, but had it on them all the time.
It wasn't big, and looked lots better than what you get nowadays from the tax department.