I'm looking to run the Emerald Spire Superdungeon soon and thinking about the initial location of Fort Inevitable. The town is controlled by a Lawful Evil group of the Hellknights. As a result, I was thinking about not allowing any of the PCs to be a Paladin class. These Hellknights, being LE aligned, would seem to be the antithesis of LG/LN paladins. I would believe that if a Paladin were to ride up to town, they would seek to challenge the Paladin practically at the front gate. That's something that could bring the module to a screeching halt before it begins.
What in the rules or other source materials would support or repudiate that view? Or vice-versa: Would a Paladin see himself as honorbound to attack these Hellknights as beings of evil?