Why forwarding to STD numbers are not allowed?

When the subscriber is in home network and trying to set the FTN as STD number intendedly(for example to his home number in different state),is there any restriction from regulatory that operator shouldn't allow? I think this is a valid use case

Basically, the call forwarding data is entered in the 'B' side (called party side) of the subscriber database and therefore, the forwarding is in the control of the called party and not of the calling party. It is therefore, that forwarding charges are charged to the called party. This is because, if forwarding is done, litigation happens between the calling party and the service provider as he can object about forwarding a local call he made to a distant location without his knowledge and will and make him to pay for that.However, the called party has no control on who calls him. 

Since selective call barring within a forwarded direction is not possible, either in the calling party's data base or in the called party's database, all junk and sundry calls also will get forwarded to the called party and he has to pay for forwarded protion of the calls which also will not be in the interest of the called party. 

Coming to your point, why it cannot be allowed if the called party can afford it or willing to pay,  is question of universal acceptability of the product. 

Now as you mentioned, if you wish that you as a called party would like to get all calls coming to yours home location forwarded to your phone while roaming in a distant location, it is already available in the national and international roaming facility which you can selectively activate. This is different from call forwarding. In case of roaming, the calling party pays for calling your home location and you as the called party has to pay the roaming charges. This is entirely different from "Call forwarding feature"

I hope the matter is more clear now. Any way you doubts are genuine, because, as head of technology in 1995, it took me long to convince our product management team why we should not allow call forwarding to long distance stations, when the GSM had just made ready for operation.

Hi Sir,

Thanks for the response.

But I want to understand that if a user can afford these heavy charges I think he should be provided this facility.

And also I don't understand why if the charges are high why it will end up in litigation??