For the pumps that the mute button doesn't work: carry a small screwdriver, 1/8", flat blade, insert into center of speaker then pull sideways to severe the coil wire.
It doesn't effect the operation of the pump and takes a three second poke and twist. With no legitimate use of the speaker it would be months before it is noticed. Think they would scrub through tens of thousands of interactions with the pump and find that one person who leaned in a bit? Doubtful, and if so, minor vandalism charge and a small fine for months of quiet peace. Worth it in my book.
Some electronics have a way to test the system if the speaker is functional and can potentially kill the system, so that’s not even remotely true. Also, maybe they have to manually check the pump every morning when they turn the pumps on as part of their start up process.
You are a fool if you think stuff isn’t able to verify and test itself in todays age or they don’t have an employee checking stuff semi frequently…
In either case it wouldn’t be hard to go through a days footage, even easier if the system self tests and tells you when/if the problem occurred.
That speaker is also used for communication with the cashier, for example a disabled person requesting assistance. Or in my personal experience, the pump not working right and them telling me to put the handle back and start over.