My family and close colleagues know that I do this, but I do not bring it up in conversation. Recently a niece got married and was going to Bali for her honeymoon. In the midst of other advice on her first international travel, I did mention to her about crediting her intl carrier miles to a US carrier, and oh btw get the co-branded cc and you will have enough miles to get you a second flight for free for your first anniversary.
So perhaps it is just more context sensitive in terms of the amount of info you give, and to whom you give it to.