user rights and caller restiction

I have noticed lately that user rights and caller restriction is not working well.
When there is a shortcode for restricting international calls you can go around that.

I will use a 0 as prefix and european standards in my examples.

Normaly pressing a 0 will give secondairy dialtone from ARS.
This is done by making a system shortocode:
0N
dial
0
50:Main

In ARS 50 you have:

N
dial
N
line id of your trunk(s)

When a user needs to be restricted you can make a usershortcode or use userrights.
For example this user can not make international calls.
Often we make a usershortcode or a user right shortcode:

000
Busy

line id 0

This can be bypassed easely.
When pressing 000 give busy but when you press just a 0 and wait you get secondairy dialtone from ARS because there is no match with 000 !!!

What needs to be done is making a new ARS for restricting international calls and in this case it is ARS 51.

Then make a user shortcode or a userright with the next shortcode:

0N
dial
N
51

In ARS 51 you have the next shortcode's:

N
dial
N
line id trunk(s)

But also the next one:

00
busy

line id 0

Now in ARS there will be a match no matter if the user waits for secondairy dialtone or the user does not wait for the secondairy dialtone !

This means that for every user right with call restriction there needs to be an ARS entry for it.