"If you have nothing to hide, you have nothing to fear," is an excuse I've seen to try to push to get your info.
That may be true, yes. However, there's something those looking to harvest data by demanding your info hate to hear that rings truer:
You have a right to privacy.
You have a right to privacy.
You have a right to privacy.
You have a right to privacy.
You have a right to privacy.
You have a right to privacy.
You have a right to privacy.
You have a right to privacy.
You have a right to privacy.
You have a right to privacy.
You have a right to privacy.
If someone thinks you're doing something shady, they can come back with a warrant. Make them work for it. If they can't access your info without explicit permission, they don't deserve it. Otherwise, no one is entitled to your info outside of necessary channels and that is still up to you to decide. Don't let anyone blackmail you into giving in.