You're right, there is a place for the lowly bell! They seem like a "Fred" accessory, but in situations like that are just the thing.

I've got one on my commuter, it's small and inconspicuous, not like the big old chrome ones we had on our kids' bikes.

I've found that a lot of pedestrians are confused by the "on your left/right", because they're not up on the jargon of cyclists, skiers etc.