Well the problem arises when you realise that scientists actually DON'T know what they are doing , for if they did , they wouldnt need to conduct the experiments. One of our big flaws is blindly believing they know everything. Let me put things into perspective for you , we have no idea what causes gravity , can you believe that , they just dont know , they dont know what causes lightning (if you dont believe me do some research on it), They just discovered a new planet in 2003, their "standard model" just doesnt add up (by their own account) ,this people dont know as much as you all think they do, i've looked into their "theories" , and most are not much more than observations. They are looking for the boson higgs , a theoretical particle which plays some role in creation of mass , this particle was thought up , to make their model fit more properly, however , there is ZERO evidence of it's existance , which is the main purpose of this big experiment , in which more than likely they will find nothing. To the guy saying mini black holes dissapear , when have we seen this happen ? You say they are different than the big black holes and that the big black holes have been hehre for trillions of years , yeah , but they originated sometime from somewhere , we dont know how black holes behave , in fact , black holes were only accepted as being abundant some years ago , we still have no idea of what they are , we've just come to understand they are everywhere in our universe and play an important role (there's a massive one in the center of every galaxy) .

But dont be fooled by what you read (yeah mini black holes just evaporate) LOL , there is no prove that happens , it could happen , but it could as well just grow. They've also said the machine has the potential to create a black hole every second , there's also the posibility of black holes joining , and growing. If you think about that they actually know (very little , almoost everything is speculation) , then you realize the real chance of a black hole evaporating to a black hole growing and swallowing the earth is 50/50. Here are some links to articles discussing what happened with their fist test of the lhc.
http://www.sciam.com/article.cfm?id=particle-collider-magnet
http://news.bbc.co.uk/1/hi/sci/tech/6522189.stm
You so blindly believe this people know what will happen when dealing with the unknown when they make simple mistakes designing a machine with components we're familiar with ?

You have to be INSANE to just believe creation of mini black holes and strangelets post no threat , or be seriously brain washed by the science community. After much research of many many things science related , I came to the conclusion that we really dont know much about anything , most everything is observations and theories , so you shouldnt just believe something because you see it in a book , it could just be an accepted idea , rather than fact.