The more the producers and judges tried to down play him, the more people voted. Just like Sunidhi insulted Tia again and again, two judges- Abhijeet and Aadesh- kept on taunting ishmeet. That only resolved people more to vote for him. Just like Tia, he had a sweet voice, but was not well trained. He had the natural talent though. The junta loves a person with potential who is not technically best. Case in point - Prashant Tamang.
Once public voting comes in, sympathy and identification are two big factors. People feel sorry for someone who is trying, yet not getting appreciated. There is no rationale to public voting.
I have seen people from Bengali nd North-east are crazy about Tia. I went on a short holiday to Kolkata, there are banners everywhere asking for people to vote for Tia. Her mom is also in Kolkata University. On Facebook, Nepalis love Tia so much they are asking how to vote for her. Apart from that, I believe Marathis also prefer Tia to Bhoomi as she stays in Mumbai. yet Tia never asks for Marathi votes like Bhoomi did. Apart from that, Tia's looks are too pretty. she has a lot of males going crazy over her, including my 25 year old brother, my 10 year old cousin, my 18 year old juniors.
overall a lot of factors are in favour of Tia. i think she has every chance to be Indian idol 5.