I mean, what kind of an idiot ...
... walks into a huge, dense field of grass higher than a man's head in the first place, without taking some kind of measure to ensure he could find his way out? Cal and Becky didn't even go in together holding hands. That's the very least I'd have done, to ensure we didn't lose each other.
Before I went in, I would have searched the church property and especially that truck to see if there was some rope that I could attach to the car for a life line. Barring that, they could have gathered up some rocks, sticks, anything to mark their way out.
Or how about this? They were on a long trip, surely they had some luggage and supplies in the car. Why not break off the antenna and tie a piece of clothing to it so that one of you could hold it up above the top of the grass for a beacon?
Didn't these peoples' parents read Hansel and Gretl to them at bedtime when they were kids?