In the age of identity theft, customers feel that marketers are violating their privacy when they

In the age of identity theft, customers feel that marketers are violating their privacy when they: resell information from marketing surveys without permission
information from surveys often carry sensitive topics such as age, address, total salary, or even social security number.
Selling this to another party without consent is considered an unethical practice.

Complementary goods. they go together, thats why one price increase and the others demand increases