As the night unfolded, I began to realize this concept is quite genius!
After watching the crowd (who were all so friendly), they were so much more receptive to one another than the usual club gathering.
I recently attended a Lock and Key event at Blue Martini in Brickell.
And yes, the females wear lock necklaces while the men wear keys.
Judging from the popularity of the events (attendance has doubled at each new gathreing) this formula for love seems to be working.