Had it out of BCN once... talk about the worst experience ever. The DL gate has a special cordoned off area across from it for the SSSS'd pax, along with armed security guards who barely speak any english while they go through all of your stuff painstakingly slowly. They start the 3rd degree inspections about 45 min before boarding and don't finish with all the pax until everyone else is boarded. Nice way for BE/STE+ pax to get that 'seamless' experience.