I've posted this before but I'll repeat it anyway.
I've learnt that you should never deny a cat anything it wants to eat. I once tried feeding my beloved moggy a cheaper type of cat food than he was used to. Unsurprisingly, he turned his nose up at it.
During the following night, I awoke to hear a voice coming from my living room, as if I'd left the radio on. I crawled out of bed, to switch it off. As I got to the foot of the stairs, I realised that the voice was saying "Hello? Is anyone there? Do you need help?".
Yes, my moggy (obviously distraught at not having the right type of food) had walked over my telephone, pressed the 'hands free' button, and then dialled 999!
If your cat likes salt and vinegar crisps, let him have them. Otherwise you'll find yourself reported to the feline equivalent of ChildLine! ;-)
Chris