AirWolf
Honorary Master
- Joined
- Aug 18, 2006
- Messages
- 24,404
IMO the nature of the service suggests that if person A requests a reverse-charge callback from person B, and if person B trusts person A enough to do this, then person A and person B will know each other sufficiently well enough to know that person B is a contract customer...
Pretty much what I was thinking as well - if you call someone / they call you often, then you are very likely to know which network they are on and whether they are on prepaid or contract.