I've found the exit through the gift shop to be a typical arrangement for museums both here in the USA and overseas.

I took my mom to Paris in 2002. We had just lost my dad, and I thought it would probably be good for her spirit. Growing up, we had a number of Picasso prints around the house. There is a Picasso museum in Paris, and I thought she would enjoy it. It was on the east side of town, not really close to a Metro station, so getting there was a bit of a hassle. We are trudging along the sidewalk when it starts to snow, so we ducked into a patisserie for coffee and Danish. Coming out, we walked past the museum, which was not well marked, but finally made our way back. The stroll through the museum ended up at the gift shop, and I asked her if she wanted anything. She said, "No, I never really like Picasso that much. I just had friends who thought he was fantastic, and they always sent me prints of his." Let's just say that after all the trouble, I was not amused.