It's a very interesting situation! A miniature medal is not an official medal and in some quarters it seems to be worn as a simple item of 'bling'. Somewhere I saw a report that a person wearing miniatures used the defence that it is the full size medal than can't be worn and as the miniature is not seen as even a copy of the appropriate medal, anyone can wear it.
As there are now a shed load of 'commemorative' medals available to be purchased, the problem is set to get worse - latest I saw was genuine and commemorative medals mixed up on the same chest.
Old Duffer