Actually, $justloaded is even less necessary, because ON LOAD already does this. In other words, if you actually are just trying to thank your users for using your script, you should be handling ON LOAD, not ON START. If the situation is that a user might unload the script and load it later, you should have some kind of %myscript.isinstalled variable to test whether it was previously installed anyway.
So in fact, I see no real use case for testing whether mIRC is "starting" in ON START.
