I just feel like it is so much of a 'numbers' game, no pun intended. Its very much a low rate of return by giving out business cards, but like you said... when they do contact you...!! Filters out the crap, same thing women do haha!

I would think something along the lines of "Here's my card, text me something cute later" would take the pressure off of them contacting you first, while still requiring the chase from their side as well...