No one holds a gun to your head and forces you to post personal stuff on here do they? No one holds your family hostage and wont release them unless you post while travelling do they?
You have freedom of choice to post or not, and how much personal info you reveal about yourself on here and elsewhere on the internet. If you have posted such personal info and it could come back to bite you and are then worried that a country flag will give your identity away, then whose fault is that really?