Some people are called out for not understanding the instructions that they see on doors and other places. These instructions aren't really that hard to understand, but we just have a hard time understanding them because of our attitude. While we are careless in understanding some instructions others can tend to be very ambiguous.
This instruction that we have here is really ambiguous and sounds funny. We really do want to know what the rule makers constitute as garbage and what they constitute as trash. We want to know both of these things because only then can we form an understanding of what these guys are looking for. All they are looking for right now is some angry customers to be honest. Why would you come up with such an ambiguous instruction if you want to help people?