If they assume a kid needs to be able to read to ask questions like that, and still don't make the connection that if he's asking questions like that, he must be able to read, then they aren't as smart as they think they are.
If he is using the letters to figure out what the pictures are (hilarious -- and sounds like something my DS would have done), and they still can't make the connection that he knows what the letters are, then they aren't as smart as they think they are.
There's a theme developing here. I doubt it will help you, though.
It's probably just like a kid who learns to walk in private because he doesn't want anybody watching (my brother, for one) -- the bigger a deal it becomes to them, the less he wants to do it in front of them. I was that way with lots of things -- it wasn't that I couldn't say "please", for example, it's just that so many people made such a huge deal out of it, I wasn't about to do it. If only you could get them to just ignore the whole reading thing, they'd probably stumble upon him in the next room, reading the encyclopedias.
