This action was used in Reach's Race gametype with the index of 90 (Action90 in ksoft) and 118 in Halo 4. For the past few months, I've been trying to figure out what this action does. I decided to give it another try and I'm glad I did!
Here's how it's used in Race (the official Reach gametype):
<Elements> <E type="Action" name="Action90"> <Param type="PlayerReference" varRefType="ExplicitPlayerType" dataType="Iterator.Player" /> <Param type="Bool">True</Param> </E>
I changed the boolean parameter to False and spent several minutes dicking around in both unmodified and modified gametypes like I've done many times before. This time, I noticed something different: You were spectating other players but not the checkpoints like in the unmodified gametype.
After some more testing, this action appears to control whether you could spectate over players or respawn objects.
Now, what to name this action... comment with your suggestions!