Destination Wedding - Packing for Mexico Customs

You don't get charged Mexico customs for anything that is for your personal use while you're in the country. Customs applies only to items you are going to sell or give away while you are there. Thus, they would not apply to any decorations you would throw out or bring back.

Bigger issue is coming back into the US. If you receive more than $800 in gifts plus items you buy there, or more than one liter of alcoholic beverages per person, you'll need to worry about US customs.

As for gifts, you're into a grey area. What the law says, and what the customs agents will say, are two different matters. At one point, we brought in a whole computer for my sister (who lives there). This was back in the days before laptops, so we had a computer, a monitor, a printer, etc., in a stack higher than my head. When the customs agent asked, I explained with a straight face that I was a lawyer, and needed to be able to work during my trip. They let it through. Conversely, there have been a lot of stories of Mexican customs agents declaring that items they want are prohibited, and then basically stealing them.

You're probably okay if the items in the gift bags are of low value. But nothing is guaranteed.

Lol Mexican customs is a joke. Last time I went (January), I guess they weren't ready so they just let the whole flight out of the airport without punching passports or asking why we were there. Lol but maybe sometimes they're strict