Easy solution - use the rubber tip caps. If it's really an issue I would think signage would caution people to not use the carbide tips on popular trails. This is the first time I've ever heard of such a complaint.

As a follow-up to my post above, I looked at who made my REI hiking staff. It's from Komperdell and REI calls it the "Guide Staff". I really prefer the ball head on these over what you see on most poles. I got two more for my kids. What's great about these is the height adjustability for people of all sizes.

REI Komperdell Guide Staff