Hey Empenguin,
I have the same concern. My wife and I have many postcards that are very valuable to us and we risk the chance of these being lost or damaged in the process. I decided to scan all the cards and posted envelopes and print out the copies to add to my file pile

...
I figure if they request any originals then I will send them. I think the only reason they would request originals is if they felt the copies were fake.
I hope this helps you!
canthai