ok, to I am going to try to explain why it is likely that the experimental has always been in the first three and will probably continue to be so.
Notice that if you look at what people had minus the experimental, everybody had the same two scored sections before the break, and the same two scored sections after the break, even if they had them in a different order. This is intentional. This means during the break, no test-taker could give a "heads up" to another test taker because everyone has seen the same material and yet to see to the same material.
However, now lets consider the possibility that some people had section 2 as experimental, but others had section 4 as experimental. The people with section 4 as their experimental would have three scored sections before the break, whereas those with section 2 would have only seen two scored sections. This would mean that if you discussed what you had seen with other testers during the break, it would be possible for some testers to "give away" some details that could help other testers out who still had two scored sections to go. We all know you are not supposed to discuss the test during the break, but LSAC at least recognizes the reality that this could and very likely does occur.
Until recently, everybody even had the experimental during the same section. However, it seems due to some allegations that this enabled some test-takers to more easily deduce what section was experimental while taking the exam, which allegedly allowed them to cheat, LSAC has seemed to recently had test-takers taking the experimental during different sections starting around February of 2008.
And as much as you may not like being the guinea pigs for future tests, it is the part of the process that allows the test to be standardized and you are now benefiting from past test takers who went through the exact same things as you.