Marek

One framing that has changed how I think about it: on a trail, sound is a shared resource that cannot be opted out of.

I can look away from something ugly. I can walk past litter. I cannot un-hear a speaker, and neither can anybody within a few hundred metres, for as long as it takes them to get out of range.

That asymmetry — one person's choice imposed on everyone in earshot with no way to decline — is what makes it feel like more than a preference dispute, and it is why the reaction is stronger than for things that are merely unattractive.

For the immediate term, before you build anything: a head net.

It costs almost nothing, packs to nothing, and completely removes the specific misery of flies going for your face. Not a solution, but it makes the situation tolerable while you sort out the vent, and every hut like this should have one hanging on a nail.

On the group dynamics, since this started as a disagreement among friends: the thing worth being careful about is the effect on newer climbers watching.

Risk normalises through observation. Somebody two months into the sport who sees a respected friend doing this is receiving information about what is normal, and they are the least equipped to evaluate it.

That is not a reason to forbid anything. It is a reason for the person doing it to be conscious of who is present, which is a smaller ask than the argument you were having.

The reliable answer is to stop using a road map and use a topographic map, where the information is present by design.

On a topo map, contour lines crossing a watercourse form a V that points upstream. That is not a convention somebody chose — it falls out of the geometry, because the valley floor is lower than the ground either side, so the contour has to bend uphill as it crosses. Once you have seen it, you can read flow direction off any stream on the map at a glance, including tiny ones with no name.

Second method on the same map: read the elevation figures at two points along the river. Water goes downhill. This is slower and it is completely unambiguous.

Third: follow the junctions. Tributaries join the main river at an acute angle pointing downstream, like the branches of a tree pointing towards the trunk. At any confluence, the shape of the join tells you which way everything is going.

If you want to start seeing them, the conditions matter far more than the effort:

• Temperature. Snakes are most visible when they need to warm up and least visible when it is too hot or too cold. Mild mornings after a cool night, and the shoulder seasons, are the productive times.
• Edges. Where two habitats meet — forest and clearing, bank and water, rock and grass. Far more productive than the middle of anything.
• Look at flat objects. Sheets of bark, boards, corrugated metal, flat rocks. Lifting these carefully, towards yourself so the object is between you and whatever is under it, is how surveys actually find them.
• Slow down and stop. Movement is what you detect and stillness is what they do. Standing still for two minutes reveals more than an hour of walking.

Do that for a couple of mornings and your lifetime count will change substantially, which is itself the answer to your question.