@Overtheline: I agree with you that this student already knows her answer and marginal students in general will likely encounter problems in their extreme reach schools. But they have a much better chance to be successful in Brown.
There is a reason why so many students would like to come to Brown. I have posted this Ivy League graduation requirements before (http://features.columbiaspectator.com/news/2016/04/14/are-columbia-students-the-most-stressed-in-the-ivy-league/). If Columbia is asking “Are Columbia students the most stressed in the Ivy League?”, by the same logic, Brown probably could ask the opposite question.
Not that studying in Brown is easy (actually is a lot of work), but because students know they are lucky to be in the least stressful environment. Yes, some students still cannot graduate and some still struggle. But if they went to other “pressure cookers”, the results would be much worse. In the worst-case scenario, they can take 30 courses all in English to graduate (a joke heard in school). In Brown, there is no need to take five courses per semester. Some people start to break down when they need to take five courses. At Columbia/UPenn/Yale, students must take five courses per semester at least four times in order to graduate. To us, it would be hard to maintain a happy/healthy lifestyle while keeping a high GPA when doing that.
I still encourage them to apply to Brown. If they could get in, they would be given a golden opportunity to thrive here.