Yep, the termites have been thwarted...without any need for humans or cats to vacate the premises! There was a bit of a miscommunication at the pest control company -- the only reason we'd initially been asked to leave for the duration of the treatment was because someone at the firm had been under the impression they needed to spray aerosol stuff in the crawlspace (under the house). But since they were just injecting insecticide into the dirt under the garage, there was really no conceivable way for any of it to get on or near any of the resident mammals. Which meant we got to stay in the house -- I shut everyone (myself included) into the computer room while the exterminator did his work, but even that was mainly to avoid getting underfoot.
I am sure the cats were NOT disappointed by this turn of events -- I mean really, they got to do exactly the same thing they usually do on a Friday afternoon (which is to say, sleep), no need for anyone to be shut up in a carrier and carted across town. Hooray! But by the same token, the experience of trying to plan a short evacuation has led me to figure it might be a good idea to have a "drill" once in a while, just in case we all ever DO need to get out of the house for any length of time.