We said at the beginning that the most important form of discipline in self-discipline.This is where it pays out dividends, if you have it.
On a patrol, your goal is to get as close to not being there when you are as you can get.
Much of that advantage may be obtained after dark, because even with the availability of night observation devices, most people won't have them, so darkness itself still confers a powerful advantage. Provided you do your utmost to leave no trace, in three important areas.
Nothing about you should make the merest sound, even while moving.
You should plan your footsteps so as not to be heard.
You shouldn't talk, ever, unless it's unavoidable, and at that point, it should be muted, muffled, or whispered.
Your gear shouldn't rattle, jingle, squeak. Everything from footgear to pack should be placed and broken in so as not to give the slightest notice of your arrival or passage.
This includes attachments, like slings, on weaponry.
This should be checked by you first, then by the patrol leader before you set out, and anything that makes noise secured, taped, padded, or whatever is necessary to silence it.
If you carry your water in a camelback-style bladder rather than canteens (suggested), you can suck all the air out of the bladder through the drinking tube until there isn't any, and you will drastically decrease any sloshing noise from it.
Hard items in your pack should be placed and padded among softer items.
Everything should be secured tightly so it doesn't shift inside its carrier.
Buttons, toggles, and speed clips are better than Velcro or zippers, because quieter.
If present, zipper pulls should be replaced with 550 cord knotted loops, and the loops tucked under fabric/material flaps, or elastic bands, or taped down, to prevent them moving and rattling in any way.
You should practice moving weapon safeties from safe to fire slowly, and with a minimum or absence of detectable noise. Nothing in nature makes such an obvious and unnatural metallic "click".
If ammunition or magazines carried rattle, pad them with useful items: spares socks, or extra weapons cleaning patches. Putting a folded muslin bandana/arm sling or battle dressing under magazines will raise them a little to pull out easier, quiet them, and give you additional first aid supplies.
Consider a trick illegal aliens have used in the southwest desert for decades: blanket booties on soft to moderate ground. A doubled rectangle of blanket big enough to wrap each boot is placed and held with baling wire, shoelace, or 550 cord. It muffles boot footsteps, and eliminates most visible track sign on soft ground. When worn out or not needed, it can be removed, cheaply replaced, and discarded with other trash after the patrol.
And FTR, radios should be on silent mode - no beeps, etc. - and can be used with headphones and earpieces (and should be, always), and you can make a mouth-sized cup out of rubber or silicone that surrounds the microphone, so you can talk without being heard nearby. And the sound output to earpieces should never be loud enough that someone nearby can hear you either.
Nothing in nature is reflective except snow, ice, and water. Nothing on you should shine or reflect light. Anything worn to shiny should be painted, dyed, or taped over, down to even boot eyelets. Daylight and moonlight reflected will be seen 10-50 times farther than the human form can be seen.
If Killflash items are available for your weapons scope, binoculars, or other optics, make use of it. If not, you can make a field expedient with a piece of ladies' dark nylon hosiery, and elastic bands or tape to hold it in place, stretched over anything reflective, while still retaining the ability to see through it for its intended use.
Skin shines too, in daylight and moonlight. Camo up, or wear spandoflage, a knitted mask, or something similar. Even a hood made of solid camo, olive drab, or other earth-toned t-shirt, with eye holes, if better than bare skin.
At night, light use should be minimized and filtered. Red is the least energetic color in the visible spectrum; no white light should ever be used at night. It can be seen for miles. For the same reason, no visible flame or firelight either. A single match is visible for 10-15 miles at night in a dark expanse of desert or open plains. Showing such a light is like ringing a bell, or shooting off a flare, if anyone remotely observant is about.
Fire use in general should be avoided on patrol, or at most, of the buried-beneath-ground-level variety, and exceedingly small and smokeless. They also obviously provide a thermal flare that creates additional IR signature, and create smells detectable by humans for distances of hundreds of yards, and 3-5X that far by tracking dogs.
Trash and Tracks
For "minimal impact" backpackers, the mantra has long been "Take only pictures; leave only footprints". For any sort of patrol, don't even leave the footprints.
Anything you packed in, you pack out. Anything.
Food, wrappers or cans, batteries, ammunition/brass.
All of it is permanent forensic evidence of your presence, visit, group size, level of equipment and provision, origin, etc.
If you don't leave it behind, it isn't there to find by anyone later, ever.
Take another lesson from illegals crossing the southern border: brush out tracks, and minimize or eliminate the ones you leave.
If you travel in inclement weather, rain and snow will eliminate your tracks for all but close pursuit.
If you travel over hard ground, sign will be minimal.
If you carefully brush out sign (your last man's 6-o'clock watch should include this duty), you'll make detection or pursuit by amateurs impossible, and extremely difficult even for trained tracking parties. or other patrols who may cross your route.
The safest way not to be detected, is not to leave anything that lets anyone know you are or were there.
Going undetected is life, and getting detected can be death. And in bad times, going on a patrol will probably include the fact that your team is on your own. Fieldcraft include being a giant non-entity in the field, in the same way an attack submarine makes less noise than the water around it.