>Other stuff - you don't have to tell me, but I'm bringing it up because that's the responsibility of the vendor publishing the XML and if you don't let them know and fix their problems they'll just hoist that same crap onto the next guy trying to use the data/api. So I make it a point to always point out these things to whoever is responsible for providing the data. Mostly it falls on deaf ears, but occasionally you get lucky and it actually gets fixed...
Ah, that, gave up. They are already on some 19th version of it, and I was probably the 213th guy to find this, so if it wasn't fixed by then, it never will - everyone worked around it.
They had one banal problem: they demand that each person whose data go across has at least one phone number, and it has to be specified as home, work, cell or other, up to four numbers. Except they use only home number when communicating this further down, not the first available number in some order. Now that so many people have 2 or more cell phones but no landline (all three of our daughters do so), this makes for many cases where the end result is an address without a phone... where we provided 2 or 3. We told them about this during the early tests of our interfacing with them... in 2015. Still no change.
I already have a canned response if any of our customers complain.