It would really improve the ease of adding simple scripts to non-script chatters mIRC. Trying to explain the simplest of script language to someone who doesn't know and is not interested anyway is still the most retetitively challenging thing about scripting.

The only issue I can see with it other than the forementioned access is accuracy of the pasted code being transfered into a script would need to be perfect, pure copy paste from the owner without any text alterations as some scripters favour replacers and colour themes, and then there are other possible reasons for inaccuracy like lag or disconnections... In my opinion it's a nice idea, but would be hard to impliment effectively.
A better way of doing it would be a popup dialog when you are transfered a file: accept / deny / accept & install
Then the script will be complete, and the person recieving the file doesn't need to turn it on/off simply click a button.

But I'm not sure if thats possible, to over-rule the incoming file dialog for mIRC.