asp.net mvc - View Model Identifier -

i attempting started on new asp.net mvc4 project , have few questions regarding view model security.

say have class represent application users

public class user {     public int userid { get; set; }     public string name { get; set; } } 

and class represent tasks application user

public class usertask {     public int taskid { get; set; }     public int userid { get; set; }      public string task { get; set; } } 

my coworker seems think view model representation of usertask class should not contain userid security purposes (to prevent people tampering userid).

example

public class usertaskviewmodel {     public int taskid { get; set; }     public string task { get; set; } } 

i can not life of me find documentation supporting claim , haven't been able straight answer.

is common thing? should viewmodel "hide" specific properties view security purposes? understand if data comes model binding tampered with, trying figure out preferred method/best practice scenario.

exposing userid potential security concern, because:

1. you revealing information ,
2. it can tampered with.

if listing tasks different users, need know user each task. guess obfuscate userid, or when interact task (edit/delete), can check user has access.

if user allowed interact own tasks, there no need include userid know user is.