I feel the need to comment on this issue due to this possibly being the most egregious case of treaty chess I have seen in some time.
Treaty chess is the cynical exploitation of treaties built around trust, common interest and friendship between two or more alliances in order to negate the ability of an alliance to receive assistance from their allies. This can take two forms:
Chain-baiting is the result of an alliance having a treaty or treaties that make it extremely inconvenient to directly attack, thus triggering all manner of defensive treaties. The treaty-chess player instructs an alliance or alliances to attack the desired targets less well connected allies in order to compel the target alliance to "take the bait" and attack the bait alliance. Due to agreements made prior to the war, this relieves obligations of defense due to non-chaining clauses, opposing coalitions, or whatnot.
2) Treaty Conflicts.
The second and more commonly used exploitation of treaties in treaty chess is to get alliances to counter or attack a target alliance where the attacking alliance has treaties which are also held by the target alliance, therefore making it impossible for the target alliance's allies to defend them without violating their treaty with the attacking alliance.
The first instance I find more acceptable than the second, as the target in the first instance, their allies should recognize what is going on and defend their ally regardless. The second instance I have long considered to be an abuse, and alliances should not agree to be used in that way.
The rationale for treaty chess and the arguments as to why treaty chess is ok that I have heard largely involve the treaty web, and how offensive action is inherently more difficult than defensive action (due to there being a hell of a lot more mutual defense clauses than optional aggression clauses) but ultimately treaty chess involves exploiting the ties that bind alliances together for cynical ends. This goes both ways. Not defending an ally because they are obvious bait does not diminish the fact that they are still your ally, and they signed their treaty in good faith with you.
Treaty chess is the ultimate dehumanizing element of coalition warfare, it reduces your alliance down to a NS value and a treaty list. Alliances that do not contest being exploited or sacrificed for treaty chess abandon their sovereignty in exchange for better odds for "the coalition", but where will the coalition be when the war is over? Your coalition partner today ordering you to hit your ally's ally instead of defending your own ally is your enemy tomorrow, who rejoices at your diminished state, fewer allies, and damaged credibility.