According to research bottle caps are one of the biggest source of beach litter because they float and end up washed up. They are also exceptionally harmful to animals that confuse them for fish and end up consuming them.
I don’t think anyone who is against the bottle caps directive is serious about protecting our environment. It’s a minor change with an outsized impact.
Wouldn't you just fill it up from ... a tap in the washroom?
And yes, I'm fully aware that a water filling station will probably be just as nasty, but it's the thought that bugs me.