Just to make a little point that I have made before. Most police in Italy don't know the law well or would just not bother, but----
The Italian regulation states that you must wear a helmet in a 3 wheeler unless it is fitted with a survival cage or a roof and seatbelts. If it is not fitted with a survival cage and is fitted with seatbelts (the M3W) you must wear a helmet and the seatbelts.