The ASX sector classification is there to assist investors with...

The ASX sector classification is there to assist investors with research, it does not preclude companies from going about business. You are correct in that if an ASX listed entity goes about changing its dominate field in that it operates in, then the company needs to recomply with Chapters 1 & 2.

There are ways transactions can be structured for the benefit of the company and its shareholders that seek to reduce this costly exercise of recomplying with Chapters 1 & 2, QBL is company that comes to mind it's sector classification is materials, which has exposure to Bauxite and more recently Medical Cannabis. Recently Medical Cannabis is an exciting area for quite a number of ASX listed companies, companies that have even hinted at such exposure have seen there share price increase many times...