I'm just setting up my first eth shield on an UNO. Found the sticker on the underside of the board under the foam pin protectors, good.
This seems like a funny place to put the sticker. If I leave it where it is then as soon as it is mounted on the UNO it becomes unreadable. This is not helpful for troubleshooting when you have multiple UNO + eth shield units. So I have relocated my stickers to the top side - there is what appears to be a free area close to the micro SD mount.
Prudence calls for the question to be asked. What are the implications? Am I interfering with the operation of the board by relocating the glue on the sticker to another place? Presumably the thinking is security - one person sets up the combo, knows the MAC, assigns it into code uploaded to the board and there should be no further user need to display or know what the MAC is?