As far as a restaurant is concerned, why would they really care? It might annoy customers, but as long as the tables are still filling up, I feel the restaurant is more than happy, because they're still making the best of their available resources (tables and wait-staff).

It's a valid point how the artificial constraints are the envelope and the time, because the way she listed the rules was, clock starts when you open the envelope - it's almost a a ploy, or a method of trying to distract someone. Imagine, if you were handed an envelope and were told "there's money inside there", wouldn't you immediately start to wonder "how much?" and you would immediately want to open it. She restricted this thought by applying a 2 hour time constraint, from the time you open the envelope, which almost forced the students to think twice about jumping to the money. Instead, all the groups achieved something without ever really having to open the envelope. I think it was interesting, and a job well done.