I read something a year or so back about one town (can't remember which one) where the council had put pads on lampposts for people to stick there gum and which were easy to clean away. They also had fines for anyone caught throwing gum on the floor. Pity more place don't do that.
When I was a student, I had a cleaning job. The woman whose house I cleaned, used to leave her gum on any surface in the house. I often had to remove it from windowsills, the table, kitchen units, etc. I never did like gum much but that put me off for life.