Chewing gum is pretty disgusting stuff. When the taste has disappeared, usually after about 30 seconds’ rumination, you can swallow it (yuck), wrap it and bin it, or spit it out (gack).
It seems the last strategy is widely favoured among those who are devotees of the cud. It’s pretty difficult to come up with a way to encourage people to wrap their chewings…if I could do that, I’d invent a way to recycle the damn stuff as road paint (it usually sticks to roads and pavements so hard it costs huge amounts to freeze off).
No, today’s invention is a stopgap. Realising that people will still spit gum out, I suggest supplying them with liquorice-coloured gum. When that hits the deck, it becomes largely invisible, saving councils all those cleaning up bills.