It's a charming habit. I imagine one of the packaging designers devotes a very small amount of his time to creating new little guys appropriate to the crisp or crispy snack, and voila! nerdy people like me to are delighted to discover a fresh design.
However, it is not confined to Walkers. Hippeas, we tried the Sweet & Smokin' flavour, have their own little guy. He is sporting a CND peace sign and making a V sign. Hippeas want you to know how cool their crispy snack is.
Then there's Kolak. This little guy comes from their Hot & Spicy Crisps Black Pepper Flavour. The design is a little basic but I like the heart.
Then there's this extremely well-dressed little guy from Metcalfe's popcorn. I'm not certain why he needs a top hat but he certainly is well-dressed.
Let's not ignore KP Skips. The reluctant taste testers and I tasted Tingly Prawn Cocktail and discovered this slam dunk guy. Not a super exciting design but they made an effort to change the generic little guy into something a bit more interesting than what you usually see.
I will keep my eyes open for more examples of little guys throwing their rubbish away responsibly. Do let me know if you can point me in the direction of other examples. I am sure there must be others out there that I have yet to spot.