Is that possible to use event for an object "outside" the script ?

I try to detect and fire an event everytime player are moved from a quest script, but so far, I didn't find how to do that.
I tried to do something like that, but it didn't work :

Actor Property Player  AutoEventPlayer.OnLocationChange(Location akOldLoc, Location akNewLoc)  ;do somethingendEvent

It seem that event can only be used for the items attached to the script.
I though to attach the script to the player, but I fear that this will conflict with another mod how change player script. Is that the only way to do this ?