The Player's Handbook says that to execute a charge a creature "must have a clear path toward the opponent, and nothing can hinder [its] movement (such as difficult terrain or obstacles)" (154). Can a creature that possesses the subtype incorporeal pick as the target of a charge a foe if that charge's path takes the creature through the space a corporeal ally or corporeal foe?
That is, with the understanding that incorporeal objects, objects composed of force, allies and foes that possesses the incorporeal subtype, and a handful of other things could still spoil such a creature's charge, is the subtype incorporeal sufficient to render largely moot the necessity of a clear charge path to the incorporeal creature's foe?
Note: You can read more about incorporealness on Monster Manual 310–11, Dungeon Master's Guide 294–5, Libris Mortis 140–3, and the Rules Compendium 64–5; I mean, I did, and I couldn't tease an answer to this question from them, so maybe someone else can? This question was brought about by the latter part of the Dungeons and Dragons BECMI adventure module that I've adapted to 3.5 that has seen the PCs encounter—honestly—far more than their fair share of creatures possessing the subtype incorporeal, them having had multiple encounters with gangs and even swarms of shadows as well as lesser phantoms. Sometimes battlefield conditions have seen these creatures forced to make unusual decisions that some of my players now question mechanically… and that I now question myself. This is one of them.