How are tax deduction (80c) supporting documents submitted?

AP (Trainee) (83 Points)

17 December 2012  
Salaried employees (like in our organisation) usually declare their entire tax liability around the end of financial year and on the basis of that the employer, with the help of chartered accountants, prepares form no 16 and distributes. At this step, each employee is asked to submit copies of documents to avail tax deduction under 80C. Suppose for some reason all documents are not with me so I am not able to claim 80C deductions at that time and pay excess tax (through TDS). By the time when filing e-return I have received the documents and I show excess tax paid in the ITR-1 but where am I supposed to submit the copies of documents showing amounts for deduction u/s 80C? How does the ITax dept know whether an assessee is cheating or not?