More dumb questions since I know nothing about Bivy's. I don't think I've ever seen one.

Could I use the bivy alone in warm weather?

Do they improve the temperature rating of the bag?

Do they need a footprint or some substitute?

Can you get out of them if the zipper gets stuck? (I never zip my mummy bag all the way as I'm paranoid about that.)

Thanks again for the suggestions.
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