We are currently working on several methods to prevent using your own client scripts and taking control of the server. The current solution was thrown together in around 20 minutes as i don't have enough spare time to work on LU that much these days and the other developers are either as busy as me or are being lazy.
The new solution that i am working on should stop this as well as many other forms of cheating but it will take time to implement properly, if we half-ass it then it will be bypassed and render it useless.
As for not letting client scripts call internal lu functions... i have thought about adding this and may add it soon but its easier said than done as squirrel doesn't have any native way to tell the difference between the two. Disabling calling internal LU functions isn't a full solution anyway as client scripts can still be used to cheat in the server. The original idea behind client scripts being able to call internal LU functions was to enable server owners to create a fully functional admin panel which could control the server easily but i did not think that anybody would be able to use their own scripts (oh how wrong i was).
To be honest, this bug isn't as bad as it was before the two patches. Yes there are ways to get around it but it isn't as simple as sasha makes it out to be, its probably only him that has taken the time and effort needed to pull this off at the moment and he hasn't been a dick about it
The next patch should fix it once and for all anyway but as for when it'll be released... it really depends when i have time to implement all the ideas and test them.