We had a similar situation here in the early nineties with a few very vocal people claiming swan deaths were directly caused by fishing weights. They had x-rays of swans with lead weights in their gizzards, where they have grit to grind up their food before swallowing it, which had caused them to ingest the lead. While I'm sure it is not only possible, and that some swans died as a result of this, I seriously doubt it was a significant cause of swan or waterfowl death. Lots of swans are killed because they fly into electric power lines for example, and I'm sure you could find a lot more corpses under power lines than you would lead poisoned birds on the water. The trouble is, it only takes a very few, very vocal, people to start shouting and it becomes an issue.
I would be inclined to resist all bans like this as they're not usually based on a significant risk to the animals they're aiming to protect. Many other human made threats are far more significant, but it's relatively easy to pick on something relatively minor and make the uneducated general populous agree that "something must be done". Politicians fall over themselves to line up with these type of causes, and so we end up wrapped up in pointless regulation and added expense which results in a few people feeling smug and very little difference to the animals!