Actually I'm a "rulester"...so I keep the windows up.
They do have a walk through part where the guests can go up in a 2 story gazebo and feed the giraffes by hand (for a fee, of course). It's their healthy food, not the junk people would give them if left to their own devices, and it's up to the giraffes to stroll up and eat if they want it.
I loved it....they have immensely long blue tongues that they wrap around the food (and frequently your hand) to take it.