It's a bit of both. The article specifically mentions the CODE specifies minimum sq ft. You could still put a tiny "house" down if that house had met code. The code is the reason why it was unworkable even for a single unit on a plot.
(and in any case, since the topic was code enforcement, article states "North Las Vegas Code enforcement took action" )
(and in any case, since the topic was code enforcement, article states "North Las Vegas Code enforcement took action" )