Be polite, smile a lot, try to know a few words in spanish.
FWIW I just went through Cabo customs three days ago. I have a Nauticam housing for an LX10 and of course the LX10, no strobes just video lights. I also have Sealife Sportdiver for the iphone. BTW last year I went right through. This year I had to put the stuff on the xray machine. They xrayed, the agent asks do you have a housing for camera. I replied yes 2 of them. Lets see he says. I unpack the Sealife Sportdiver, he says ok. Any drones. No. Okay senor, we are done. That was it. Never looked at the Nauticam housing, I didn't pay anything.
However I was prepared for them for nonetheless. I bought the Nauticam housing and LX10 used for $800, I had a receipt saying so. I also do many fish surveys for REEF.org. I had letter from them (REEF.org) stating I was specifically doing volunteer work, and not a professional. Lastly I had a printed statement that says at least $500 is duty free according to Mexican Government.
I would also add, check your trip insurance. This nonsense of charging people for camera equipmnet is nothing more than an illegal shakedown. Just like trip insurance should cover theft and loss. It should cover illegal shakedowns. If you have to pay, make sure to file a claim with your insurance company, immediately. If you have to pay see if you can do it with a credit card. On the way out of the airport be on the phone with the credit card company disputing the charge immediately as an illegal shakedown. Let the Mexican Government prove to the credit card company it is not an illegal shakedown.
Be polite, smile a lot, try to know a few words in spanish.
