I've shot several destination weddings ever since going full time a few years back. One in Costa Rica, one in Hawaii and one in Mexico, so I feel like I've seen a bit of how the destination wedding industry works.
A year ago a bride contacted me about shooting her wedding in Mexico. We agreed upon a price and she signed the contract. Part of the contract is that I would be handling my airfare and hotel.
Two months ago I touch base and give her timeline suggestions, as I do with all my brides. She replied and let me know that everything was good to go, but the resort charged a $500 fee for using an outside photographer. She asked me to pay half, which wasn't in the original contract, but I agreed to help prevent any tensions. In my agreement to her, I explicitly stated that my business was to cover no other associated costs.
Fast forward to today, the wedding is on Saturday. She hit me up with another email saying my assistant and I will need $150 day pass to get on the resort to shoot the wedding. I really don't feel like stomaching another $300 fee. I have since built an EXPLICIT clause into my contract to prevent this from happening in the future, but what should I reply with for the time being?

