Is it a market or a bazaar?
A: I hope not. This used to be an issue with returners who were willing to take a pay cut to get back into teaching. Technically, once you have been put on a particular point of the main pay scale, that position cannot be renounced. You can, though, give up any allowances or recruitment incentives.
If the NQT you mention had argued for, say, extra points on account of prior experience one year but then offered to give them up the following year just to secure another job, then that would be reprehensible.
Teachers' pay and conditions have been carefully drawn up by a review body after consultation with employers and professional associations. Certainly, it is not for individuals to play fast and loose with them.