Also, I like this technique because I found a couple of interesting use cases where it was really practical. One was for a project where I needed to render the two eyes of a 3D anaglyph separately, but I wanted to render them both at the same time as to not have inconsistencies between both eyes on particles and shaders that were random. I was able to render it this way (one pawn for each eye). In another instance, I wanted to render a stencil pass but did not want to use the normal multi-pass render because all of the passes come out horribly aliased (because at the time they are taken, I believe, post-processing has not been applied). With this workaround and some post process materials for the camera, I was able to have a synced, antialiased stencil mask in a single pass.
Sadly, I also found that there are visual artifacts when using split screen that I was not expecting to exist (such as shadows displaying only for one player but not for the other, and some post-process effects).