So for the venue I will put down an allowance for alcohol and when that runs out it's cash bar. A bridesmaid told me about the danger in that, she said one of her friends put down $2000 and an hour in, they told her the allowance ran out. There was no accountability except for what the bartender said he served.
I was thinking of making tickets, possibly on VP that said "ONE BEER" OR "ONE COCKTAIL". They can redeem for drinks and I can have the bartender collect them in a large jar for me, then I can count and I can make sure it was served.
