TRCN stands for Teachers' Registration Council of Nigeria. The body was implemented to curb quackery in Nigerian schools. The much ado about it in our national discourse is as a result of the following:
1. Some Private School Owners: There are many mushroom schools especially in Lagos. The proprietors of these schools are only after anybody that can accept their peanuts. Such proprietors are among the people that are kicking after the 2018 deadline that has been set by the professional body.
Such proprietors don't believe in professional. They believe that anybody can teach and as such they employ based on who bargain les with them. After all those who police external exams are not immune to bribery so they can always capitalise on them and justify their employment of quack teachers.
This same set of proprietors are not happy on the technological development that exam bodies are upgrading to because they will be no room for cheating during exam if WAEC and NECO apply the same JAMB technique.

2: The Non Certified Teacher: These are the second group of people that do not want TRCN. It is akin to showing them the exit so this is why they are protesting against the 2018 deadline. They are in many private schools and they hardly search for another job because they will not be considered.
So if you know of a teacher in a private school that is not paying much and the teacher does not want to leave, the teacher may be one example.

3: The Born Teachers: Unlike the number two above, teachers in this category are qualified because they have their certificate. But one thing you should know is that teaching is an exclusive preserve of those that have NCE and B.Ed. Any teacher without this certificate is a dabbler in the profession.
So some of them don't want to comply to the directive of the TRCN management which is directing the to enrol for an additional one year programme and get the requisite knowledge (teaching methodology).
This set of teachers are found in both public and private schools. They are are also scattered in the higher institutions. Their protest is that they have the requisite qualifications but they have failed to understand that they are not exposed to teaching methodology. They are dabblers.