In my current ACKs campaign, my players are exploring the Quasqueton dungeon of B1 fame. The place was ruled by bandits and beastemen sent by the evil clerics of the nearby Caves of Chaos. Finally, the players were able to defeat the chiefs of both bandits and beastmen, and only a pair of bands were left in the dungeon: seven orcs and four gnolls.
In their next expedition, the players found the seven orcs. The leader of the party, an Elven Enchantress with great Charisma and a good selection of proficiencies, rolled a very good reaction roll. The orcs vowed before the people that have defeated their leaders, and asked to be able to serve the heroes. Now, the group has not only 4 human hirelings, but also 7 orcs. It's not the first time they use beastmen as cannon fodd... errr, I mean, as respected hirelings: the Elven Enchantress had Charmed before some gnolls that died some adventures later in a fight against goblings.
Later, the group found the last band remaining in the dungeon: four gnolls. The Elven Enchantress, once again, rolled a very good reaction roll. But the gnolls are 2 HD monsters, bold, and they despise orcs and humans, so instead of asking for joining the party, the gnolls said they were willing to left Quasqueton at once, no need to have a nasty fight. The party agreed and the gnolls left the dungeon.
Now, this was a perfectly good adventure, and right now the party is still exploring Quasqueton with their orcs.
When the time to give experience came, I give them XP for the gnolls, as they had managed to send them away from Quasqueton. Using a good reaction roll, some roleplayed negotiation and the fact that the gnolls knew they were outnumbered and leaderless.
But I didn't give them XP for the orcs, because I feel the orcs had not been defeated, but had become a resource for the party. In the same way that magic objects found in the dungeon can be either sold (to give XP) or used (and then, they don't give any XP).
Reading the rules, I think perhaps I should just give the XP for the recruitment of the orcs, as they had been defeated and are not (currently) a threat anymore. But then, I feel like I'm rewarding twice the party, with XP for defeating the orcs and with a force of minions to use in their adventures.
What do you think?
P.D.: I've asked about it in my own blog (in Spanish): Monstruos que se unen al grupo en ACKs ("Monster that join the party in ACKs")