Horse muck collecting bags?

I live on a busy main street and it a concern when riders bring their horses onto our road (especially the younger ones). There has been so many horses rearing with the traffic noise. This is once concern but also we have "no horses on the pavement" notices but they constantly use the pavements and leave their piles. I can understand why the riders do this from a safety aspect but it is against the law. Do riders have any objection to horses being kitted out with those poo collection bags when they are going to use the streets? You see them in many European countries and the USA. I have recently visited Savannah and was impressed that horses are not even allowed to p water without the owner notifying the authorities (they leave a float on the "spillage" and this area is then cleaned and disinfected). I suspect the horse owner has to pay for this but, hey, that's one of the pleasures of owning a horse. What do you think? PS - I love horses and do ride a little - in fields and stables.