This guest had been invited the day before and would have every reason to expect that the information was known for well more than 24 hours before the "event". This person was unknown to the wife, and generally speaking, if someone you don't know is going to be in your house, you like to make a good impression by having things neat and tidy, and you don't know what sort of food they'll be expecting but I bet they expect more than leftover hash.
Also, I don't have kids, but I *was* a kid. I was a kid with chronic medical problems and an absolute terror of needles and doctors. A trip to the doctor for several hours that involved invasive lab procedures with needles would have debilitated me for most of the rest of the day. I would have required a great deal of attention afterwards and been quite the handful for my mother until bedtime (I often milked such things for all they were worth).
On top of this possibility, the wife doesn't get notice of the guest she doesn't until about 8 hours or so before the event?
Clearly she managed to deal with it, but I can certainly understand being annoyed by it. If he'd just managed to mention it the previous night when he got home (because he clearly KNEW about it then), it would have made a huge difference.
-- Siobhan Perricone "I ain't afraid of your Yahweh I ain't afraid of your Allah I ain't afraid of your Jesus I'm afraid of what ya do in the name of your god" - Holly Near