We have a main schema which are using for generic content at many places and across blueprint for many websites(markets).
Now one of the website(market) wants one extra field but all other do not wants to see this in their publications.
I suggested to rename the fields for all other markets like (Not in use) but they are not agreeing on this as well.
What are the possible solution to hide the field from the child publication?
Without knowing the full context it is hard to give an advise. But in general I would not recommend to hide fields (even though it’s possible with a GUI extension in 2011 and with some hacking in 2009). I think Tridion offers plenty of options to solve the puzzle out of the box. For example:
With security on folders you can limit access to the market-specific schemas.