Yes, that seems to be so. We could easily get some indent into the style for the templates, I think. Do you think it's worth while? It's relatively rare that the full width is used anyway, so I don't see that it would create too much problem.
I think that the framing and background colour makes input and output stand out nicely. On the other hand some writers seems to prefer indentation as well, and maybe it is a bit more stylish. If it can be done without causing problems, it may be a good idea.