Consequences of showing higher income

Respected CCI members, we know the consequences of inflating fake expenses & decreasing incomes but i would like to know the consequences of showing higher fake incomes & not claiming deduction u/s-80C to pay taxes to improve credit worthiness for the purpose of loan?? Is claim u/s-80C is optional or compulsory? Does department issue notices against th assessees for cases which are not beneficial to them like in the above case?