occasional? Seriously? rare? Seriously?
"Source code should be written to be understood by people." Nope, Source code should be written to be executed. If people can understand it easily, its a plus point, not a baseline.
Considering that the keyboard is the primary way we write sources, I find it difficult enough to keep my fingers in speed with my thoughts. In addition to that if I have to press tabs to align each of the statements in my 'for's, I'll be left in a much poorer way.