[忍]

When you Banish a Spirit, there's an opportunity to roll Summoning to gain services:

If you (or another magician) has an action before the spirit departs, you can use Summoning (p. 300) to try to get it to owe you some services.

Has anyone used this before?

[Marcus]

honest to god I didn't even recall that was an option. Sprite jackers!

[Kiirnodel]

I've used it against a player once. An Astrally projecting magician used Banishing on a spirit that one of my players summoned, but he did so immediately after the spirit had just Materialized. Because of the spirit's loss in initiative, it didn't act again until after the magician, so the opposing mage was able to re-summon it.

It was actually a very interesting situation, because from their perspective, all they noticed was that the spirit materialized, and then something felt weird and the spirit just didn't do anything. The next pass, the opposing magician commanded the spirit to turn on its former master, so it did. Shenanigans all around.

Long story short, that astral magician pulled all sorts of havoc on the group until the PC mage finally looked around in the astral himself, and immediately got dropped with an Astral Combat attack (or a Mana spell, I forget). Then the Astral mage popped back to his body, cast Invisibility and slinked away.

[忍]

Why wouldn't the Spirit just be Banished upon the action's resolution? Why wait until it's initiative pass? Bullets hurt when you get shot.

[Kiirnodel]

Well, the Banish spirit action might be considered misleading in that regard. The spirit doesn't depart until it gets to act again. The action of banishing doesn't immediately rip a hole and send it packing, that's disruption (filling the spirit's damage track). So because the spirit didn't act until after the magician did (and he re-summoned it), the spirit never had an action on which it owed no services, therefore it didn't leave.

Pass 1:
22: Spirit uses Materialization (rolls 1d6 for lowered initiative, loses 4 initiative)
19: Magician Banishes spirit, reduces services owed to 0 (Spirit will leave on next action).

Pass 2:
9: Magician re-summons previously banished spirit (gets 2 services).
8: Spirit turns to new master, waiting for a task.

If the spirit had gone after being banished, it would have left. But because it was re-summoned it didn't.