All you needed to hunt an infil was a good sense of stamina rate loss, good hiding places, bumps in the road, EMP nades and/or a Sweeper.
I used to see an infil if they even jerked a little, considering I've always been in third person looking at minimizing my own visibility during movement. If I had it, used Dark Light more for minefield navigation in third person (had vegetation turned on).
With patience, I can crawl into any position without making any move that created even a glimmer. Passed by a lot of backdoor defenses that way.
Just have to watch out for those DL sweeps and friendly plasma and stray lasher and bulletspray. In some cases, I was behind the enemy after more than a minute of crawling up to and around them undetected and random friendlies would toss in a plasma nade, spam thumper rounds or something else. Especially annoying if you informed those friendlies earlier...