Risk
Sex outdoors isn't illegal itself, doing it in such a place that you're likely to be spotted and cause an "offence to public decency" or some such thing is where it starts to get iffy.

Straight cruising probably doesn't happen because of the risk (real or perceived) to the female of being attacked. Apparently, getting the crap kicked out of you is reasonably common in gay cruising (so I've been told by gay friends).
( SteamedCleaner, Mon 27 Apr 2009, 1:46, Reply)