I'm doubting it for that exact reason. You'd need to add an intake vent and that'd notn be too good.
I'd go for the bag in box if you're getting a postmix setup. It's not like they go bad quickly since the bag-in-box will still be otherwise sealed. If you, or a kid ever drinks a juice box or caprisun until there's nothing left, that's kind of how the bag in box works. The syrup is taken out and the bag collapses, still leaving no air coming in to foul the syrup.
Best to just dispense soda water into a glass with syrup otherwise.
Secondary: GF Czech Lager
Waiting to be kegged, Italian Primitivo
Kegged&Ready: GF Orange&Coriander, GF Honey Lager, GF chocolate ale, GF English ale, Island mist (zinfandel), Island mist (cbry malbec).
Bottled: Infected Mead, Dry Hard ciders, Accidental Sorghumwine, various unnamed.