Reversing bleepers are classed as “horns” so are covered by the same laws as sounding your horn.
They use to switch off when lights turned on, but the ■■■■■■ elfs decide O that’s dangerous, Volvo have a on off switch.
I will run mine for 10-15mins before I go to bed, if I’ve had TV etc on, I hate the click click sound in the morning’s of flat batteries.