For those who did RSVP postcards, what was your rate of USPS loss? I really want to do postcards to reduce invitation envelope bulk and be a tiny bit more cost effective. However, some of my save-the-dates were lost in the mail (athough they haven't made their way back to my parents' house), so I'm worried about an even smaller piece of mail getting stuck between junk mail and disappear....
Thanks in advance!