That's great. Thank you all - now I know. I asked because sometimes I just want to go out to the shop quickly to buy a beer and I only take enough money for the purpose. But now I have to take all my paperwork in my wallet and then protect it to make sure I don't loose it on the way or back. I went to the movies the other day and when I left the theater, my wallet fell out of my pocket. Luckily I check before I left but it could so easily have been different. But in the thirteen years that I've spent in Thailand so far, not once was I asked for my passport except at the border.
I'll have to look into this small copy thing...