If she got the individual shots of tequila from different servers at different bars, between 3pm and 11:30pm (over 8 1/2 hours) how would Carnival have known how many she had, and in particular how many in a time frame closest to her fall. Surely someone drinking four shots of Tequila between 3pm and 5pm would have “recovered” from them before 11:30pm, unless what she did was “bar hop” around the different bars on the ship the whole time - which is what I believe she was doing.
When I had a drink package, I still had to present my cruise card every time I ordered, so they do keep track of how many drinks you’ve consumed on board.