If you've never seen a diplomatic bag you would be excused for wondering how a Selectric would fit in it ;)
"Bag" (also called "pouch") is a bit of a misnomer. It's not limited in shape, size or weight by the Vienna Convention so it can really be anything that can be transported, including ISO containers.
For example, one of the toilet pumps of the ISS was sent in a diplomatic bag to the US, which is around the same weight as one Selectric https://www.newscientist.com/article/dn14017
I remember reading about one incident in the 1980s were a Russian truck of 9 tons was turned down at first at the Swiss border but could pass through later.
It's important to note that the "bags" are only exempt from legal search and seizure at e.g. customs or by police. If they're not equipped with effective tamper-evident seals and/or escorted by a trustworthy courier at all times then they can (and probably will) be intercepted. It's tough to gain access to the small ones, but a shipping container is much harder to keep under watch at all times. It only matters if you get caught with your hands in the cookie jar after all.
I'd guess the typewriters weren't shipped in tamper-proof containers and were simply altered en route. I once read a story that I can't find again about the CIA intercepting a shipment of (what I think were fighter planes?) and disassembling them overnight, then putting them back together to be on the train again the next morning. It was a great story, I wish I could find it again.
Learn a new thing every day. Maybe the term 'bag' should be retired for this purpose.
I think you've just figured out how to get Julian Assange out of the embassy. Place him in the diplomatic bag. Now we have to find a way to classify him as an 'article for official use'.
"Bag" (also called "pouch") is a bit of a misnomer. It's not limited in shape, size or weight by the Vienna Convention so it can really be anything that can be transported, including ISO containers.
For example, one of the toilet pumps of the ISS was sent in a diplomatic bag to the US, which is around the same weight as one Selectric https://www.newscientist.com/article/dn14017
I remember reading about one incident in the 1980s were a Russian truck of 9 tons was turned down at first at the Swiss border but could pass through later.