Convention hotels typically have staff 24 hours a day. They pay shift differentials. They can arrange for extra staff for big events.
The correct thing to do is for the hotel convention manager to say "I will get you a price for that by tomorrow," and go talk to the banquet manager, who will check:
- current price of oranges, and estimated yield and wastage
- number of juicing machines needed
- number of extra staff needed
and come back with a price that reflects the costs, the hotel's desire to make a profit, and their desire to land this particular meeting.
Quick estimate:
2 oz of juice per orange, 14 oz glasses, so seven oranges per glass, 700 glasses, that's 4900 oranges. Three oranges to the pound, 1617 pounds. Allow for 10% wastage, 1800 pounds. $1.32 a pound, $2400 for the oranges. A person with a juicer and a knife can process two oranges a minute, that's 2450 person-minutes, we have 120 minutes to do it, so we need 21 extra people. We pay for a full shift minimum, so $15/hour for 8 hours for 21 people is $2520. We have pitchers and glassware already.
At no profit the cost is $4920 for your 700 glasses of no-more-than-two-hours old hand-squeezed orange juice, and now the convention manager will look at the total price for your meeting and decide what to price it at -- but $10/glass is entirely plausible.