Verifying physical address via a verification service provider. Are there any threats?

Question

The idea is to send address information to a service provider to see if the address actuall exist or will kick back not valid. If done over an unencrypted connection across the internet, are there any privacy concerns over just address information?

EDIT

This is in regard to physical addresses like:

1234 Washington St
New York, NY 99999

Answer 1

Without knowing what your service does, it could very much be a breach of privacy.

Suppose you are building this to verify parts of an identity in the healthcare industry. Suppose it's for a very specific purpose -- e.g. verifying addresses of patients in certain conditions or under-going certain procedures (HIV/AIDS patients, abortions, etc). If someone were to intercept that information they could conceivably find those people and harrass them.

Or maybe your service sells something, and your competitors can intercept address information. They could start advertising to the addresses, which is an indirect violation of privacy (the person at the address didn't necessarily allow anyone else to get their address from you).

I would consider this a breach of privacy.