As written though, the paladin oath doesn't actually forbid some evil deeds- like torturing villains for info or as legal punishment- though "eschew meanness" and "protect the defenseless" may cover those.

Most issues with the code come in situations where the paladin is outclassed enough that sneaking, or laying traps, or knockout poison- might be argued as preserving the greatest number of people.

In the early Realms novel The Crystal Shard, when Wulgar confronts the apparently defenseless (trapped in ice) dragon Icingdeath, he wakes it up, and his words are:

"I am a warrior of honor and will not kill you under these unfair circumstances"

Though when he mentions taking the treasure, the dragon's rage is enough that it breaks the ice.

The narration says "A more experienced fighter, even a knight of honor, would have looked beyond his chivalrous code, accepted his good fortune as a blessing, and slain the worm as it slept. Few adventurers, even whole parties of adventurers, have ever given an evil dragon of any color an even break and lived to boast of it"