Yea, scripts shouldn't be doing that. That's a recipe for abuse.
If you want to tell what scripts should and shouldn't be loaded, open them up and read them before you load them-- and then if you want, don't load them.
The potential for abuse is there regardless how a script is loaded. And people aren't going to examine a script to look for malicious content. Those who do will likely have already loaded the script and view it in the script window.
Honestly, a script designed to auto load or execute other scripts is going to be safer assuming it's been well written and tested for the unexpected. And abusive or malicious scripts aren't really a problem. Running into a script that breaks and goes haywire by typing /unsetall or unloading a priority script (i'm think NNS here) is the problem. Make sure you use a timer that's capable of independently detecting when something goes array and automatically disables everything... and make sure you have one script that always is the first to execute... and use /reload to load scripts not /load.