Quite obvious..
2 Million a night is their lowest ever right?
This year the papers and stuff keep going on about how crap BB has became..
If you even like BB your "a low life" apperantly
And surprisingly not many BB Fans want to be on BB because they dont want to be famous
This means that BB wouldnt do Public Auditions because instead of Massive Ques there wouldnt be that many meaning that the Papers and BB haters would laugh at that and would be embarressing for BB to have like 600 people instead of thousands there ussually is..
Why Email?
Well Computers are the thing of the future

Why go out on a Rainy Morning and wait for hours and hours in a big line with a bunch of Chavs when you can sit in the comfort of your own house and Email BB your Audition!
Simple as that,
Emailing will get BB more Auditionees aswell,
The people who say..
"I would of loved to go on BB but whats the point in going all that way an being turned down?"
Well now you dont have to go all that way!
To some it up and answer the Quistion
"why no public auditions?"
Its because BB are scared of being embarressed by a low turn up of Audionees so use a Computer were no one will ever know how much Auditions they get..
Accually,
If your gona audition you`ll have a better chance of getting through if not many are intrested..
Remember how unpopular BB10 was?
That and most Fans dont want to go on it?
Means instead of a 1 in 10000 chance its like 1 in 100 chance of getting in now or through to more rounds