There's another legitimate reason that kids ditch their coats. Ellen Paulsen says parents don't seem to get it: Kids don't notice they're cold, she says, because they're running around like crazy. Kids are comfortable because they're active. Just as an adult who takes a jog in cold weather doesn't need as many layers as someone who's just standing around.

Eccles agrees that his next step is to see if a cold virus is actually present before and after chilling volunteers. In the meantime, he advises kids and fashion-conscious teens to bundle up -- or risk the chance of sitting out parties due to colds.

"She's an escape artist," says Mosher. "If you manage to get the coat on her, it will be off before you're out of the car."