A few years back I was at a laundromat. The top loaders had a thingy like this and on the top it said, load line. Is the thingy a lint filter, or a load line thingy that keeps clothes underwater?
If it is a lint filter, how would it work?
It might just be the load line marker. When people are using machines for the first time or machines with which they are not familiar, like in a coin laundry, something that delineates how full to load the machine is probably a good idea. Of course, then you have the people that load loosely to that level and those that want to pack the load down like they are tamping a cannon's charge.