They wouldn’t fight the landlords because a lot of them are landlords.
They would simply lobby to have the law repealed or, more likely, vetoed before passing. Failing that, they would exploit every loophole and edge case to take advantage of it and cry to lawmakers and voters that the law is the problem rather than their circumvention of it.
I thought we were against putting trash in our water. I think bucket -> compost is better. There are plenty of strong backs that would love to put in the work for the benefit.
I personally think the fear of your brain becoming fish food might help motivate behavior change,but keeping micro plastics out of the ocean is pretty important.