That is not true.
Tank is close to invisible until you fire your first shot (typically ambush), then smoke reveals you, and you will have to move after firing shot number 2, and bring down prepared arty when you move.
Its very easy for the tank commander and gunner to see through the camo, if made correctly.
Normally, the rear end of the position is open, so you can back out and go into next prepared defense further back, during that move you are very vulnerable, so it has to be done through woods or broken terrain.
That is why it is so important to fight on your own ground, you have about 5 prepared positions, and also have marker on trees so the whole platoon know what way to take you to next position, even in the dark.
I've always preferred this type of fighting, just head to head pounding give you more than a head-ace.
Anti-tank mines where always more effective in slowing down enemy than you own tanks, unless you did it the Russian way (sacrifice tanks)
I'd love to see what happens when you fire a cannon from under a huge pile of straws. Sure, burying your tank underground also makes it invisible, but it also makes it blind, immobile, and unable to fire.