It is
defenitely a legal obligation. Section 20 of the Act is very specific that
" it shall impose " and not " it may impose ". " Shall " means do something inevitable, something that will take place, denoting an obligation or direction to do some act. Please note that " should " is the past tense of " shall ". As per the recent Supreme Court decision (not in RTI case), " Failure to give reasons is denial of justice". Therefore it implies that it is obligatory on the part of the CIC/SICs to give reasons for not impossing penalty when the PIO is proved guilty. The main problem is the non-accountability of CIC/SICs. Who will bell the cat ?