When I lived in SF, I stopped using the automated checkouts because they were too sensitive and glitchy; if you breathed on the scale they'd require a clerk to reset.
And I say that as someone who lives in the kind of city people associate with post-industrial decay.
That said, I wonder what happens at safeway during a fire or shooter.
During a fire, the gate controller will have a fire alarm input on the terminal block wired to an output from the fire alarm system that will open the gate if the fire alarm system activates. All automatic doors/gates/card access doors and fire alarm systems work the same way, fail open on fire alarm signal.
If there was a duress button system at Safeway, a signal from that could be used to automatically open gates and doors as well during an active shooter incident, but afaik it’s not mandated by code like fire alarm door and gate releases are.
Some automatic sliding double doors actually are able to be pushed open, there’s a hidden hinge in the top that allows it to open up even if the double doors are closed.
You might be able to lock it down during periods of limited occupancy, and you can rig it to an annoying alarm, and maybe try to identify the person, and ban them from future. It is possible to get variances for this, but you usually need to either be a medical or penal facility.
And I’m not talking about homelessness in general. New York has plenty but at least it’s somewhat under control. No companies are leaving or putting these sorts of barriers in place because of it.