I guess I'm on other spectrum of this debate: 'support'.

Once, for a paper (book chapter), I was re-assigned from FIRST author to LAST author after the first draft was submitted.

My story! A Thread: https://twitter.com/roydanroy/status/1265632247648063488

I was working on a research project (not as a student) but directly with the supervisor. I spent 9 months (days and sleepless nights) to get the data, do the experiments, do literature review and write numerous drafts for a book chapter. 1/n

Given that I had no obligation to continue to work for another endless months with no certainty and that I did complete the task at hand, I decided to switch to a different project at different place. And I got one, a good one! So I informed my then supervisor of my decision. 2/n

It was taken nicely. Note that by this time, not only I had completed the work, the paper (book chapter) was already written and sent to the publisher.

Now my supervisor back then knew that he had no legal boundation to keep me from working on different project. 3/n

So I was asked to 'leave'. Not that I was happy to work at such a minimal wage but I did expect some respect for all the hard work and countless nights I put in the project.

Either ways, I left and joined the new place. Academic nightmare started from here. 4/n

The publishers sent back the paper for certain revisions and formating. The publishers had our email id when we submitted the first draft so I was CCed in all the e-mails. To my horror, I was no more an author in the first place. I WAS INITIALLY THE FIRST AUTHOR. 5/n

The supervisor did mention my name in the acknowledgment section thanking for the 'contributions'. This all was done because I wanted to do something more in life, a new project at a new place after I completed my current project.

But again, what he did wasn't illegal 6/n

The new paper draft did not have my name which it was in the first draft. Had their been a condition that authors , and author sequence cannot be changed, I would still have that work under me as a first author.

Did we sit back? No, we fought back! 7/n

We wrote an email to the head the department, director of research and the dean of research with snapshots of our work for all past 9-10 months. Each of our drafts had date and time in their filenames. We had endless drafts to prove our point.

All we asked was credibility. 8/n

Seeing the thing being blown out of proportion, I was finally given the last authorship in the paper. I was literally removed from FIRST to LAST because there was no protection of authorship sequence.

Reason: I was striving to do even better in life! 9/n

It was my first reseat paper, my first research project and my first research experience! I WAS VERY DISAPPOINTED

To answer, why authorship sequence should be protected, it also has its pros. At times, it prevents unethical work process, unethical process of authorship 10/n

Looking back, I wish my authorship was protected. It was a blatant exploitation of academic power. For someone just starting into research, it could prevent destroying their entire morale.

I hav come way far from where I started but I can see why such a rule might be important!