Your end point could be debated to great lengths because "noticing something" is influenced by many variables, and I'd argue that for blending in, the edge would go to green in most cases.
Camouflage makes my entire point in this discussion. The patterns and colors used for camouflage in an environment, mimic that environment. Militaries would never send urban camo (grays&black) into the hills or forests.
Forest green or mid to dark green is the most common color that tents are produced in. It seems that it is mainly US based brands which most often deviate from this (Marmot, REI, Mountain Hardwear, SD,etc.). I would bet that the majority of tent buyers in the US, don't camp in the wild, or at least don't camp beyond designated campsites. The members of this forum excluded of course.