Identifying oekaki

Besides the artist specifically stating they used a "simple" art program, how exactly would one know when to properly tag oekaki? Jaggy lines really isn't enough to know, as one could just use the pencil tool or turn off anti-aliasing in less "simple" art programs

I've always considered "anything that looks like it was drawn in mspaint" to be oekaki.

Or have that PC-FX style. E.g. Snatcher.