Have seen these used a number of times in Mexico at restaurants/hotels and even the airport. Many of the handlers walk around with them which does scare off the seagulls and others. Until they move to another location, when they come back. On occasion they fly them. I've been told tourists don't like the results on the occasions the hawk gets a meal. I've not seen it but it's fun to watch them fly.
Back in April, we spent few days in northern Florida.
There was one popular Beach Front cafe with a large outdoor dining room. All around the perimeter wall there were large owls placed to scare away the grackles that boldly harassed diners. The birds would fly to a table and in the blink of an eye fly off with a French fry plucked right from the dimer’s plate. No crumb on the floor went unclaimed.
The grackles knew their trade and practiced it to perfection
The fierce looking owl were simply ignored
Terranea Resort in Palos Verdes CA uses birds of prey to scare away seagulls from the dining terrace. People on the path nearby can walk by and look at the birds of prey and talk to the handlers. You don’t have to be a guest to use the path through the area. You can hike through to the Bat Cave where they filmed the Batmobile coming out in the 60s tv series.