

basically invisible until the last moment: no light, wear black clothes (and often in the wrong direction)
I am unfamiliar with rules regarding traffic-worthiness of a bicycle, but in germany, your bike requires certain equipment to be fitted to the bike - reflectors on the spokes, front and rear light at night, etc. Additionally, you’re not allowed to drive in the wrong direction, unless specifically allowed to with a street sign (one-way-streets often allow for ciclysts to drive against the direction)
If those rules don’t exist in a similar fashion in italy: consider making the bike traffic worthy before forcing ciclysts into high-viz-gear and therefore reduce their willingness to actually use a bike in the first place.
If those rules do exist in a similar fashion already: cyclists are apparently not following those rules, adding another rule for high-viz-gear is most likely not going to be followed either. Maybe consider enforcing the existing rules before adding another rule.
I just wanted to quote you out of context.