Ah, oui, you meant "sablage" rather than sabrage!
 - Interestingly enough, in French you say "sabler le Champagne" (specifically to celebrate) - "sabrer" also exists, but according to the "Petit Robert" dictionnary, it is not used in connection with Champagne. So this arouses a faint suspicion that your "official" story might belong the the realm of myth.