It is like a ban but I think it has the advantage that does not make things illegal so you don't get the "state tells me what to do" people complaining because

It is like a ban but I think it has the advantage that does not make things illegal so you don't get the "state tells me what to do" people complaining because you explain it is a fair "capitalist/free market" measure. Y0u are right that is hard to measure the exact costs, but we don't measure how much it costs if the bottle lands in water but how much it costs to have the bottle collected and placed in the right place(some special disposable facilities) this will mean have the stores implement ways to collect the bottles to be properly disposed, you can add Y on top of the cost and return it to the customer when the bottle is restored to have most of the objects returned , though I know some people will not like to keep the empty bottles and bring them back to the store