I've never done it, but I've seen others post about doing a 5 gallon AG mash one evening, then boiling it the next day.
I'm not enough of a chemist to truly grasp what happens in freshly extracted wort. But I'd think that with a mashout to halt enzymatic conversion (i.e. stabilizing the mash?), and the fact that these people were basically going to bed after the MLT was drained, then waking up and starting the boil...the wort would probably still be 120F 8 hours later. I doubt lactobacilis could jump in that quickly, but that's just an assumption.
I say do it. Its a mini-mash so its not all of your fermentables if something goes awry, or if it just ends up slightly sour, the malt extract will help soften it.
let us know how it turns out.