“why the cups on top of the water bottle ?
and Melania didn’t open her water.”
We think it means the water is off the table the answer is NO, NO DEAL.
I think it is simpler than that.
Bottles with blue caps are reserved for POTUS & FLOTUS. They have been filled by a trusted and secure source.
Water bottles with a cup on top cannot be determined whether they have been secured or not. Trade-craft, keep them guessing.
It may give away that some threat via the bottled water was found out.