Does the "key to the city" open anything?

Mattster:

When the mayor awards somebody the key to the city, does it open anything?

-- Another Mattster, the Net

I'm sure you've also noticed that those official city keys are usually big plastic skeleton keys, not the fancy, round-barreled kind that fits an unpickable lock. We might have hoped our valuables were better protected. The whole pointless ceremony dates back to the Middle Ages, when you actually did need a key to get inside the city's walls. Naturally, these were carefully guarded. When some dignitary came to visit, it was the ultimate honor to present him with a key.