I haven't heard about the bubble wrap, but an alternative is to remove some in a bucket + keep it somewhere not too heated, like a garage, cool greenhouse, porch, etc.
The spawn frosted heavily will perish + often get attacked by a fungus, but some of that below may survive. Fortunately my frogs aren't showing yet.
I think maybe we mollycoddle too much- these creatures have coped with snow + ice for longer than we've been around on this planet. I get c80
Common Frogs visiting my small pond + the pond resembles a giant samolena pudding, resulting in probably tens of thousands of tiny tadpoles. If they all survived there would be a plague, but natural forces of climate, predation + disease maintain an equilibrium.
I'm not trying to stop you saving any spawn, but they will cope without our intervention, provided we give them good habitat.