Not sure it's effective, but.... the closest beach to Phoenix isn't San Diego, it's former fishing village in Mexico called Puerto Penasco. It's grown up now and a fun place to go. They are re-opening this weekend. In order to cross the border, you have to go thru a "Sanitation Tunnel". I've been going to Puerto Penasco for +40 years and we're always entertained by some of the ideas the Mexican authorities have come up with over the years to mitigate some of the influences from the north - some very serious, some comical.
Here's a link to a story on the tunnel in use in Nogales, Sonora south of Tucson -

Sanitation Tunnel