Pinning ceremonies originated when nursing schools were free-standing institutions affiliated with hospitals, and the pinning ceremony was
the graduation ceremony. Now that nearly all programs are college/univerity based and the nursing students are earning a degree the same as all the other graduates of the school, more and more schools are eliminating the pinning ceremony -- it's hard to justify having what is, essentially, a second graduation ceremony for just one group of students.
It's esp. hard for the school to justify spending school money
on a special ceremony for just one group of graduates, so more and more schools are leaving it up to the students themselves to raise the money and put on the ceremony if they want to have one -- and, if the students are raising the money and putting on the event, then the students get to have a lot of say in how the ceremony is done, and, IMHO, that's when everything started going pear-shaped with the pinning ceremonies ...
Traditionally, pinning represented the school giving you its final, official "seal of approval" that you had completed the program and were competent and ready to go out into the world as a nurse -- and that they were proud of you and didn't mind having everyone else know that it was their school you graduated from
. You were pinned by the director of the program
(the same as, when you graduate from college, it is the president of the college (or that person's designee) who actually hands you your degree -- you don't get to pick
who you want to have hand you your degree at a college commencement, do you???), and wore white uniform (inc. cap) because your nursing pin is technically part of your professional uniform/attire -- it's not just another piece of jewelry that you would wear with street clothes.
Each school of nursing used to have its own, distinct pin, just like they each had an "official" cap -- you used to be able to tell by looking what school a nurse had attended (of course, there were a lot fewer nursing schools then). More and more newer nursing programs don't even have school pins, and so there is more use of "generic" pins for pinning ceremonies.
My personal opinion is that most pinning ceremonies now have gotten so far away from the original purpose and practice that they are more parodies
of "real" pinning ceremonies than anything else, and (as much as it truly pains me to say it) it probably is time to just do away with them entirely. Nursing students these days are earning degrees from colleges and universities; the most appropriate thing is to participate in the college commencement (if one chooses to) and receive your degree along with all the other graduates. Nursing has moved on, and we all need to move along with it. Pinning ceremonies serve no real purpose any more, and are basically just sentimental claptrap.