sorry to clarify; I'm writing the article, just looking for advice and things that I should mention in it

Maybe something along the lines I mentioned where a power can increase his relative power on one front if he can leave another front unguarded, but the problem is always there of WHEN (not IF) a stab is about to happen on that undefended border?
You may even make mention of how such zones are designed in from the get-go and how some will develop in odd ways depending on how powers expand?

perhaps you could include some tactics on reducing "hot zones" and the necessity of dmz's when creating and maintaining successful alliances after the initial phases have occurred. Your article is applicable mostly in the early phase of the game but the dynamic changes drastically if you are to find and keep a successful alliance. For instance, using geographical features such as mountains, lakes, and expansive territories which are easily defensible allow for more peaceful and easily maintained borders. The more you can eliminate the "trust" factor in finding a stalemate border, the better it is for an alliance. "hot spots" should be filled and defended, and dmz's should be used at a minimum, it's all about finding a border where both parties are secure because an invasion is impossible from either player.

"DMZs make alliances much more probable, as they allow either player to forsee a stab occuring."

you don't want to rely on a dmz because as you said, a simple move into the territory signals a stab. How does this improve the quality of the border? It rewards first-strike activity and therefore is not a good choice for a border arrangment. The best strategy is to arrange security and long-term prosperity by identifying the "lowest-cost" total security for both parties, which includes a probable stalemate for the lowest invested troops so each partner has the bulk (but not all) of his resources to expend in other directions. For this reason, dmz's can be useful in the early stages to establish a base level of trust and to reveal players intentions and/or willingness to cooperate, but as the game progresses they should definitely be avoided by the use of diplomacy, negotiation, and logistical analysis from both parties.