Real Date and Time - C# : I have an audit trail where the date and time of user's time in / time out was enlisted. Is it possible that even I changed the system date and time. It ignores the system date/time that I have changed and log the real date and time of time in/ time out of the user.

This is my code. 

    dbAuditTrail.AddActionLog(userID, timeIn, DateTime.Now.ToString("MM/dd/yyyy - hh:mm:ss tt"));