It is a bit shameful that T4 law schools take the "ignorance is bliss" approach when it comes to their students. The problem is that if the schools laid out the harsh statistics regarding attrition rates and employment opportunities before you paid your tuition, then many prospective students would be dissuaded from attending altogether.
That being said, anyone attending a T4 school who does his/her proper research beforehand should not be shocked by the idea that up to 20% of students might fail out after their first year. A simple look at attrition rates and a phone call to inquire about the 1L curve and potential 2L/3L curves is enough to put a prospective student on notice. And just like the bottom 20% might fail out, the top 30% at most T4 schools have the possibility of transferring out.
If you're in the "danger zone" (i.e. LSAT in bottom 25% percentile for entering students) at a T4 school then my best advice is this...you should go into your first year with a chip on your shoulder and realize that going to class and doing the readings is not enough. Unless you completely lack an aptitude for understanding the law, there's no reason why a student who does the following would flunk out: (1) does all the readings and makes adequate case briefs (2) goes to class (3) attempts practice problems and gets feedback from professors (4) reads hornbooks to grasp concepts they don't understand and incorporate those materials into their final course outline (5) gets a hold of outlines made by past successful students and uses them as a guideline to create theirs, and not a substitute (6) chooses to study with others who work hard as opposed to their friends that they go out and get drunk with (7) adequately prepares during finals period and (8 does not procrastinate.
If you do all of the above, by the time you get to an exam, there's no reason why you would have a bad day. You would have at a bare minimum a decent understanding of the issues, the facts that trigger those issues/rules/exceptions, and a good understanding of what kind of analysis each professor is looking for. IMO, the students at the T4 school I attended who flunked out half-assed the readings, screwed around on the internet during class, never attempted practice problems, made crappy outlines or asked others for their course outlines instead of trying to create their own, and waited until the last minute to finish legal writing memos.