There's no need for others to know it if they don't know it unless they want to apply it to their lives and try it. There's no need for them to adopt the surroundings IMO and that's how they get used to what they do and as well as get used to the surrounding that they're living with.
It's all about what they used to do and believe and so the others too, that's how they're going to live and deal with the others as well.
At the very least, they must be able to adapt to their environment before they can adjust to their wishes. If they don't, I'm afraid there will be unwanted friction and it could end up causing something bad for everyone. If they can follow well, I'm sure nothing will happen and everything around them can also get better so that the environment will slowly change into a good situation. We don't want anything bad to happen either, right?
I don't see that there will be some effect for others that it will be bad for them. It's just a belief and if anything goes wrong, it's to those that have that belief and they'll just move on afterward.
Whether you don't wish them misfortune or whatnot, there's really nothing you can do with such decisions being applied by them for these beliefs that they've got like feng shui.
I echo your sentiment, it is there personal believe and they are the one who will benefits or loss if they continue to believe on such
kind of supernatural, if they lose they will move forward same deal with people who don't believe in it, they will try to win and if they lose
they will just re-try their gambling and see if luck will permits them to win. People who believes in some additional luck kind of rituals
are also people who just wanted to win.