Mobile “re-registration"

In this land of confusion, we now see the mobile service providers putting up ads requiring "re-registration" of connections in such a manner that it would seem the people who became subscribers before 28-Feb-06 are the only ones left out with possible faulty documentation/ identification!
The reason for saying this is, ironically enough, these days a person can buy a new mobile connection for as low as Taka 20/= from the kerb without the need for filling up or signing any form, whatsoever! So, how can the mobile phone service providers escape the responsibility of their SIMs being "in the wild" as they are not exercising any sort of control? As such, what's the meaning of making the "older" users march into their service centres while "identity-less" connections are being allowed to start up every day?