Religious fundamentalism in pop culture & politics
On the double date thing: I think, from what I've seen of the show, they're allowed to go on chaperoned dates. Like I think Jill and Derrick went on a double date with Michelle and Jim Bob before they were engaged (which bothered me a bit because come on, who wants to go on a date with their parents, especially considering they're both adults?) and on the date during which he proposed, Joy Anna and Jana were chaperoning.

Yeah, good point, I guess their “no dating til marriage” line is just that, a line, with no real meaning.