Though a parent might not regularly open windows in the house, it does not mean a child can't or won't.

CNN: Be aware of hidden household hazards

Some researchers, including Nancy Kedersha, a biologist at ImmunoGen (a biotechnology company in Cambridge, Massachusetts) who was one of the discoverers of vaults, think they regularly switch from open (ie, flowers) to closed (ie, barrels).

ECONOMIST: Cell biology: The secret of the vaults | The

He remembers how Tagg showed up at an open house he holds regularly in his home district.

NPR: Denied Treatment, U.K. Vet Stands Up for Liberty