She had four paying participants... made $28, but probably paid out more than that just for the food. If you feel you are in an advisory capacity to the shop owner, you might mention that no food and no fee could get more people to come in and participate. If she sells a few yards of fabric during the evening she will come out ahead of charging for admittance.
The bottom line is that it's her business and she has to figure these things out for herself if she is going to make it.