"And the resort offers rehearsal dinner packages at their restaurant which is open to the public. The packages also require the 18% administrative charges. I'm thinking we could go to a very nice restaurant & eat off the menu. I could leave a very generous tip & not have the administrative charge. I guess I just don't understand the administrative charge. Have restaurants added this since they now pay minimum wage so tipping isn't expected?"
My niece is an event coordinator at a restaurant that very frequently holds rehearsal dinners, anniversary & b/d dinners and wedding receptions. I haven't discussed this with her, but my guess is that, since they specifically mention 18%, it IS a gratuity for the person who has to plan and coordinate everything about the dinner - and believe me, there is a LOT of coordination and work involved. It takes time away from other duties. It's common for her to get to work at 9-10 am on a rehearsal dinner day and not leave until midnight. No salary encompasses that. The gratuity may be added on to insure the person doesn't get stiffed.
There's also the difference in surroundings/experience between a chosen venue and a restaurant. A resort, or a place with prettier than average surroundings, is going to charge for that vs. a restaurant banquet room.
Life without Mexican food is no life at all