Because we want one of our adult cats to lose a bit of weight, we keep the supply of dry food in a microchip-activated cat feeder. The feeder only opens when a cat with the required authorisation (security clearance?) approaches.
But that hasn’t stopped our unauthorised G Litter kittens from getting dry food in addition to their special supply just for kittens.
They simply wait for an adult cat to open the feeder, then sneak in for a feed!