I just wanted to emphasize how seriously these weigh-ins are taken. If you do not weigh in under your max allowable weight, you will be taped. If you fail the tape, you're out on R-Day...period. If anyone has any major concerns about either making weight or making tape, start working on it right now whether you know if you're accepted or not. I was a part of the summer command staff for Swab Summer 2013 and I had the unfortunate task of escorting a father to the Quarterdeck to pick up his daughter and take her home at about 1030 in the morning on R-Day, about 2 hours after she started her R-Day experience. The father was livid and the daughter was distraught but that's the policy. I had the same experience a few hours later with my own company when a "recruited" football player was sent home for his weight. The parents were in shock and so was the kid. In my opinion, as upsetting as the outcome was for these candidates and their families, this was not a surprise to them. It's specifically listed in the R-Day handbook that they will be weighed in and appropriate action will be taken if they do not make weight. Surprise! The military has standards.
So be smart, workout and change your diet if you have to. Just like with the academic portions of your application, if you want it, you have to work for it.