It really depends on the circumstances at the time, earcaraxe.
First, a reminder that gahad isn't supposed to be used as a mechanism for overtly gaining constant mechanical advantage (think roleplay, rather than rollplay).
The spell is targeted against a single ork, so would need to be cast multiple times for a larger group. It triggers the ork's gahad, but the target can choose not to succumb to it (with the usual possible consequences). And as gahad conditions are variable and personal to the ork, it's unlikely the magician would know exactly what the gahad triggers are unless he or she knows the ork really well. It's possible the magician could be attacked, sure. After all, casting the spell requires the magician to make a rude comment or gesture, and that might not be taken well.
It's intended to put orks in a situation where they have to act on their gahad (whatever it is) or keep it under control (per the description). On the few occasions in my own campaign when this spell has come up, it's been targeted against ork GM characters, in an attempt to get a reaction from them that can lead the group into taking action (or forcing the same). But as noted, it's circumstances that will affect the outcome -- it's not a spell to make orks go berzerk on command!
Hope this helps!
Take kaer, James