[fluoridation]

If you have 500 tanks and 500 cardboard tanks, someone with only as many real tanks as you have may not bother attacking. Thus, having the cardboard tanks saved you a battle.

If someone with 1000 tanks attacks, it's a battle you would not have won anyway.

[otikik]

And yet, cardboard tanks have been useful only a handful of times during wartime. Tanks on the other hand have proven their usefulness many times.