[aomagrat]

I would like to know if there are any return addresses on these envelopes, and where they are postmarked from.

[JasonC]

Why haven't any of our resident rocket scientists thought of checking at the post office level, instead of waiting for retail alarms after delivery?

[Fredgoblu]

I would like to know if there are any return addresses on these envelopes, and where they are postmarked from

Well, if they were smart AND cheap, the return address would be the same as the delivery address, so even if it got returned for insufficient postage, it would go to the proper destination.