Hi. My husband and I went to Paris in 2007. We spent the first 2 days taking pictures of everything. We did all the museums, churches, monuments, and of course the Eiffel Tower. After spending the whole day at Versailles, and using most of my memory card, I was admiring my photos on the train back to Paris. My DH told me our stop was coming up so I put on my hat and gloves. We got off the train and I stopped to take a picture when I realized I left the camera on the seat next to me. My DH tried to catch up to it, but it was gone. We ran to the underground and asked them for help and they pretty much just laughed at us.
I took over 400 pictures in those few days, and after crying under the Eiffel tower for an hour, we went on our way.
Luckily, being married to the best husband ever, we spent the last 2 days we had revisiting all the sites. I'm sure someone looked at our silly pictures and erased them all before giving it a second thought. And they scored a pretty great camera, too.
I still tell my husband that was the best trip of our lives, minus me losing our camera and tons of precious memories. He just sighs. But he does remind me that not only did we see Paris, we saw it all twice in one trip. It does make me sad to think about, but I guess in the grand scheme of things we were lucky enough to take that trip in the first place. Now I know when we go back exactly what I will take extra pictures of.

Plus, it's a whole new reason to go back.
You can also buy cases for your cards that are bigger than the little plastic one it comes in. I bought one that holds multiple cards and is waterproof. I used to tuck my cards in my wallet too. Right in the back in the coin slot. Now, the case is about 3x3 so it can't be tucked away anywhere that isn't secure. Don't worry, you'll get back to take more pictures.
PS- If someone has my camera, I was wearing a red and white ski jacket, a red, white, and blue snow hat, and jeans in most of the pictures!