We have a remote support that has never formed part of our site audit since 1997 when we first became certified to QS9000. When we transferred to TS16949 3 years ago once again this support site was not included.
We have just undergone our recertification audit (same registrar but different auditors) our new auditors feel that this support site should be named under our TS cert.
The remote site (different named organization) located in Detroit includes sales engineers responsible for selling our company and product within the automotive businesses. Once we receive the go ahead (purchase order) sales engineers maintain the lines of communications with our customers during preproduction, launch, advising us of upcoming engineering changes, etc.

What are your thoughts?

We have the exact same thing.
Our external auditors have allowed us to treat them as a supplier (sort of).
We do internal audits yearly of them. They are avaliable during our external audits for questions, if needed via phone conference.
So far (4 years of TS16949) this as worked.