Just to give an example, this is what my trailer looks like up front:
Rounded on the vertical edges, sharp corner on top, and flat roof. An economy trailer. This is primarily what I am talking about.
In looking for this picture I noticed it was difficult to find an example. It seems most trailers for sale these days have a rounded top and the front top corner is a moulded plastic piece, curved in two dimensions. More like this:
Obviously for something like that, slapping a piece of plywood on top to make a splitter is not going to help anything. At least I don't think so.