Seems like all the problem is at the distributor level. If the breweries have to pay $150 for them new and then the deposit is only $50 then basically the "street value" of the keg is $50 or less. Does not matter what the breweries have to pay new. And sorry but no one cares who's property it "legally" is after they lost $50 on a deposit, it's theirs, they have it in their posssession and as I once heard that's 9/10 of the law.
Kind of hard to strike a balance here, require $150 for a deposit taht will recoup the total cost if not claimed and lose a ton of sales due to the high deposit cost, or maybe make the return system easier to facilitate more kegs coming back. Maybe a brewery buy-back program to give anyone returning one $50 each, that would save the breweries $100 on a new keg.
And to the OP, you sound like a rabid dog supporter of each brewery out there, no one cares that much, really, no one. Take that lawful-good alignment on outta here, no one's listening cleric. That's why the keg is at the goodwill, no one knows or cares about the law, even those who should be enforcing it.