There are some users who have more than one profile and it is recognizable by finding repeated subjects and same methods in writing even by me as a non English speaker. Which policies has SE provided to stop these users and suspend their IDs? By Ip it is very easy to find it but what about people who use of different systems and IPs? I think it would be better to suspend these users not some who ask questions which you do not like. You can easily close their topics not try to suspend them. It makes mistrust in new users and the other audiences about EL&U policies.
P.S: Multiple Ids mean one user who has several Ids in one forum by using different IPs. Surely having different account is not the matter of my question as all users in this forum have many other accounts in the other forums of SE.