I have this dilemma...I made my invitations, and I thought I had a great idea when I made the RSVP cards small enough to fit in a pocket inside the invitation. The envelopes are 2.5" x 3.5", and I had to order those online from envelopes.com. When I took the entire thing to the post office to find out how much postage to put on the tiny envelopes, the gentleman told me some of them might get lost due to how small they are. Now I'm a little concerned. Is anyone using envelopes this small? If so, are you having trouble receiving them back in the mail? Are they getting lost?