I'm somewhat afraid that this lacks verifiability. What if new snow fell on a Tuesday night and I come here the next morning. Will I be able to verify that there is a sled track?

Wiki says:

"A tag/value combination and geometry is verifiable if and only if independent users observing the same feature would make the same observation every time"

(from https://wiki.osm.org/wiki/Verifiability )

I don't want to spoil your motivation, but I tend towards not mapping this.

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I'd however be interested on other mappers' viewpoints on this matter.