In fairness, there's quite a few water bottles on those tables along with some juice. Perhaps everyone was moderating the champagne with water/juice and we aren't looking at #3?
As much as I hope you are right, but ... who in their right mind would mix Veuve Clicquot with juice or water?
I mean, it's a Champagne on the cheaper side, but nonetheless, it's a real Champagne, the bottle is 40 Euros (when bought at the shop - would be much more expensive at the venue they had it).
Only nouveau riches would mix it ...