During our gaming session today, we had an issue where one of our party didn't want to stop attacking the enemy, and one of the casters took away his ability to move in to attack them using "Forbid Action". The forbidden action in this case was the MOVE action, the targetted PC failed his will save, couldn't move, then drew his bow and fired on the other PC, rather than his original target. The target of Forbid Action was a barbarian who was raging, if this matters.
FORBID ACTION
School enchantment (compulsion) [language-dependent, mind-affecting]Move: The target can take no act that would cause it to end up in a different location. The target does not resist being moved by others (and thus can be picked up or dragged, or can float along on a raft), but does not consciously attempt to move (including not directing a mount to move).
The target is free to take any actions not forbidden by the caster. For example, a target affected by this spell's demand to not move is still free to cast spells, make attacks, or shout for help.
Needless to say: Some questions were raised during this.
First: Is it an attack on the character?
We believe so because under spells there is a line about "All spells that opponents resist with saving throws, that deal damage, or that otherwise harm or hamper subjects are attacks."
Secondly: Does the target know a spell was cast on them?
We found reference to someone knowing if they were the target of a hostile spell that was cast on them if they succeeded at their saving throw; but in this instance, the PC failed his Will save.
Third: Since this was a language dependent spell: Does the target know WHO cast the spell on them?
Since someone has to give language specific orders, and the effect happens that you obey this person when you normally wouldn't, we assumed for the moment that you did know who cast it.
Fourth: This is just a clarification: If the spell wasn't language dependent, would this have changed the answers to the above questions at all?
First: Yes.
Second: Yes. It is quite blatant language-dependent compulsion spell. If the target of forbid action seen the caster, heard him saying "don't move" and seconds later discovered that he can't move it's rather obvious effect, even without making a Spellcraft check to identify the spell.
Third: He has a strong reason to believe he knows and in this case he would be right (hypothetically there could be a spell that would compel the target to follow the next command he hears spoken by anyone - then the target could believe the one speaking the command cast a spell on him and would be wrong).
Fourth: If the spell wasn't language-dependent it could change second and third answer. The caster could try to cast the spell without being seen or heard by the target (thus answering no/maybe to third question) and then the victim wouldn't know if the effect that prevents him from moving is a spell or poison slowly paralyzing him or something else without making a successful Knowledge/Spellcraft checks (which would turn answer to second question into no/maybe).