Most first time visitors leaving through the airport in La Paz, Baja California Sur, are caught by surprise when their beverages are confiscated prior to boarding.
This airport has a unique security screening process.
At every airport I have visited in Mexico, all bags are inspected by hand. The checked luggage is inspected prior to check-in, but not the carry-ons.
Then, even though you put them through the X-ray system, your carryons will be hand inspected prior to boarding.
The beverage policy, however, is unique at the La Paz International Airport. Perhaps this policy exists at other Mexican airports, but I have not experienced it.
Due to the heat, many visitors bring bottles of water and other beverages to the airport. They dutifully drink as much as possible, then dump the remainder prior to going through security. Then they buy new drinks inside the waiting area, expecting to take them on board.
You are not allowed to board a plane in La Paz with any beverages, even those purchased inside the security check point. When your carryons are hand inspected prior to boarding, all beverages will be confiscated.
The good news is … you ARE allowed to bring your beverages through the security checkpoint, so there is no need to dump them. Bring them on in, just finish them up before your plane arrives.