Did you read this somewhere or are you making it up?
Various books over the years. The smelling people before you see them trick is real; the VC had an especially distinctive smell due to the fact that they slathered
nuc mam onto everything they ate; and the part about South American troops putting on pretty damn strong cologne before going out on jungle search n destroy missions is from another book the name which escapes me.
(snip description of SF not bathing or shaving in the field)
Even regular infantrymen when they go out into the field stop shaving because they need that water for more important things. The difference is SF elicts that look all the time; rather than out of necessity -- they're not out in the field long enough to grow that beard for example.
And it's funny that you bring up the LRDG in that photo.
Fun factoid; the first SAS mission ever in North Africa; to sneak up and plant bombs on Axis aircraft at airfields was a complete utter fuckup -- everyone in that mission was killed, captured, or wounded; despite their impressive selection training.
Meanwhile, the LRDG at roughly the same time, using just standard people picked and given a rough course in driving in deserts, basic survival skills in deserts, and how to shoot a machine gun from a fast moving vehicle achieved far more success by simply driving down the runway with non-impressive people simply hanging over and hosing the place down with inciendary bullets.
Right now; I'm re-reading after a very long period the first couple of books that were written by Richard Marcinko and John Weisman together. With Marcinko, it's VERY important to apply a bullshit correction factor -- from what I've heard from people who were around at the same time that Marcinko was in the service, he was a legend -- in his own mind.
However, it does detail that after a while, Marcinko's men stopped wearing the standard US jungle boots, and went to the beta-boots that the ARVN wore, then finally to the kind of rubber tyred sandals the VC wore. Going to the ARVN boots makes a lot of sense -- because in many cases, the VC knew that Marvin the ARVN would just go out, fire a couple thousand rounds into the jungle, then go back into barracks, so they weren't that much of a problem when encountered. So if you took advantage of that by wearing Beta-boots instead of normal US Jungle boots; the VC would see your tracks and go: "Ah, Marvin the ARVN is in the area; everyone calm down, they won't press us too hard." opening them up to an attack by US forces they didn't suspect were in the area.