@Caelano, I think a lot of people don't think of GBBO as 'reality tv', they think it's a sweet, good-natured, bunting-clad baking competition where the worst stress you'll face will be criticism of your fondant roses or a soggy bottom, so I genuinely don't think some potential applicants for GBBO think in terms of exposure, publicity and pressure in the way they would if they were applying for a different type of show.
I'd forgotten Dani the GBBO contestant's really interesting blog until a pp linked it, but she (freely admitting she wouldn't do it again) says
The production crew are funny, charming and extremely helpful. They make the experience the best they possibly can, as do Mel and Sue, but they all have jobs to do and the product is not us. We are the ingredients, to be taken out and used when required for filming, baking and interviewing.
She also says judging is
not nice. TV shows a highly edited version of the ‘feedback’ you will get. Some is very positive and encouraging, all is meant to improve your skills in some way. But this is TV land not the work environment, and methods of appraisal and feedback you may be used to will not be present here.
and
Seeing yourself on TV isn’t the problem: it’s seeing the disappointment on the faces of the people you care for when you don’t appear much in an episode or you’re portrayed in a way that they don’t recognise as fully you. You can rationalise it to them, but it doesn’t feel good to see them upset about online comments or unable to work out why your bake wasn’t shown and someone else’s was.
and
Over 6 million people saw this series and I’ve been approached many times. Those approaching me have been universally kind and generous [...]. Over the ether however, the comments will be much more personal and at times vituperative: people are willing to judge all aspects of your life and personality without knowing you when they don’t have to say it to your face.
bakingastherapy.wordpress.com/2012/10/21/bake-off-confidential-bittersweet-adventures-in-a-tv-show/
That entry should probably be compulsory reading for anyone applying.