Only Owner Allowed to Run Script?

How is a script set so that only the Owner can run it?

There are many answers to that question, depending on what the script is meant to do. In general, though, if you test for llGetOwner() before you let the script do anything, that pretty much locks out anyone else.....

default
{
     state_entry()
     {
          llListen(234,"",llGetOwner(),""); // Listen to the owner only
     }

     listen(integer channel, string name, key id, string msg)
     {
          // Do stuff, but only if the owner said to
     }

     touch_start(integer num_detected)
     {
          if (llDetectedKey(0) == llGetOwner())
          {
               // Do stuff, but only if the owner touched me
          }
     }
}

And so forth ........

ETA: Of course, you can also make the script no mod and click the "running" box off. Then you're the only one who can click it back on again.

Check who is touching/ colliding and if it's the owner do stuff:

if(llDetectedKey(0)==llGetOwner())
{
// do stuff
}