British Virgin Islands - 1970's "Return To Sender" marking on local cover

Description

British Virgin Islands
"Return To Sender" marking (hand stamp) on locally mailed cover in Road Town on Tortola
The stamp is Scott #208, issued in 1970, so my guess is that the usage was in the early 1970's since there is no postmark shown (probably because it was addressed to locally - from a car repair shop to a customer, that the post office didn't postmark it because they returned it to the sender after seeing that the address was undeliverable).
Interesting postal history item for the specialty collector of auxiliary postal markings.
--> This is a type of cover not seen often here, simply because these kind of covers are returned to the sender and would stay on the island...
Cover is approx. #6 size (6" x 3.5")
The cover had been re-opened upon being returned, the flap is present and has a minor tear in it (doesn't detract since it's on the back flap...) from being opened by the original sender (presumably to remail in another envelope and properly addressed...)
There are no markings on the back of the cover.
Shipping only via tracked mail within the USA, and standard airmail to foreign destinations (not tracked and sent at your risk)