Recently when I travelled by 07149 SC GHy Special,I came to notice that although Sleepers as well as AC coaches were almost 80-90% full,but there were only 2-3 person/general coach..that means GEN coaches in Specials dont attract much crowd & thus fully Unreserved specials should be avoided by IR...actually the reason is GEN coaches in Long distant trains are crowded by migrant labours & they've lil or no access to Internet/IRI...so seldom they come to know about those specials & those who make advance reservation obviously know about the presence of special train & thus Resvd compts are usually crowded.