Cairns are a really mixed bag in the Rockies. Alpine ecosystems can take decades or even centuries to regenerate. Having a cairn on a poorly marked trail can be really helpful and is more naturalistic than signage while offloading the burden of the rangers to maintain those signs. Where it's used to mark a specific established path, a cairn is good. Most cairns up there don't though. People go off-trail to collect rocks that are established crevice habitat, then put them in an ornamental cairn for a photo. Others take more rocks and add to it, each one furthering the ecological degradation. People who do follow cairns as trail markers are then incentivised to go off-trail which can compound the damage or risk their injury.

I dismantle any I see that aren't for pathfinding.