Neutral/Evil alignment

[Anymage]

I get where you're coming from, but that's not entirely how it works in D&D3.5...If actions completely beyond a character's control had no effect on their alignment then this use of the atonement spell would not be necessary, would it?

3.5 has classes who can lose features if they act out of alignment. Restoring class features to a cleric or druid is the one place in the examples where the 500xp cost is referred to again in one of the uses. It's unclear whether XP cost element is about the spell as a whole vs. how much is just about its ability to undo class-based alignment gotchas.

Also, hoboknight is playing 5e and 5e made a deliberate point to move away from alignment being so closely tied to mechanical effects. It's very unclear how much either short or long term magical compulsion would have on someone's alignment, ignoring effects specifically designed to do so like the helm of opposite alignment.

Another good practice to get into would be warning your players before they do acts that would ping them evil (based on their knowledge).

Player: "Okay, we're going to unload a volley of death into the pool."
GM: "Well, you don't know what's in the pool, and it could be innocent. So if you do that, it'll push you towards evil."

If they want to disagree at that point, it's better to have the discussion then rather than the more awkward one after they've done the action.

Player: "But it could hurt us!"
GM: "Yeah, well, you're right. It could. Not being Evil means that sometimes things are harder, as you don't want to hurt innocents. You'll need to figure out a way to ascertain what's in there or protect yourself. Or you can be Evil. That's your choice, I'm fine with either."

Unless the DM would do the same if the players were about to ambush an actually evil combat encounter like an aboleth, giving them information when they're about to ambush an unknown creature tells the party more than they'd reasonably know. And if it were just ambushing an innocent creature acting under what they considered to be reasonable intel, that's something that should trouble good characters but not enough to really alignment ding them.

Additionally, while a "are you sure you want to do that?" from the DM is a classic sign to consider your actions, a certain degree of murderhoboism does come from players who enjoy the combat angle of the game and are looking for times when they can play up the part of the game that they like. Discussing what bits of the game the players do or don't like can be more helpful than just discussing points of moral philosophy with them. (Also, I don't know how much I'd want to discuss moral philosophy with player B since our core assumptions seem very out of whack.)