It’s also important to consider what is behind the dead zone. It may be a vital territory meaning that your opponent will risk airforce to clear your zone of anything up to three or more inf.
A common example is in Revised. For instance, Russia has a stack in Ukraine. Germany has a stack in E.Europe. So the German player puts an inf in Balkans as a picket. This has happened more than once when I have played on Gametable online. It should be a novices mistake - but this happensmore often than you would think so the Uk sends a bomber over Balkans and clears it and the 8/9 Russian tanks can have a pop straight at Germany or even if Germany is stacked:Italy.
Even in situations where the German player has put three inf I’ve taken the risk of two ftrs and a bmbr if I’m confident that the Russians can get Germany next go.