anyone know if it's safe to freeze them? i know plastic water bottles are a big no no for freezing, but the juice pouches, like the honest kids ones in the foil type container, do you know if there's anything in there that could leech into the beverage if frozen? the box doesn't say, 'do not freeze' or anything like that. can they explode?!? if you've done it, did they thaw by lunch?