No, never been benighted unexpectedly. But I rarely do day trips, so I've almost always got full overnight gear with me anyway.
Two honorable mentions:
1. Climbing in CA with a few friends about 10 years ago at a popular crag about 2 miles into the woods. Someone wanted to get that one last climb in, and by the time we cleaned the anchor and packed our gear, the sun had long since set. We started back up the barely visible trail to our car, got into a shallow valley, and could not see our hands in front of our faces. None of us had a light! It was kind of amazing how quickly panic set in. Embarrassingly quick, really. Thirty seconds of panic yielded a flip phone which, when opened, provided just enough of a glow to make out the boot tread and get us back to our cars (this was before the days when all phones had flashlights). It was humbling to do the slow walk back to the cars, half hoping and half dreading the possibility of meeting someone coming in the opposite direction, as we ascended the trail with the phone lit up a couple feet above the ground. Since then, if I'm going into the woods, I'm bringing a headlamp, probably two.
2. Last year's annual President's day Presi-traverse backpack attempt. We generally try to get over Madison, Adams, and Jefferson on day one and camp in Sphinx Col the first night to set us up with good options for day two. Last year, the Presi's had received several *feet* of snow in the preceding week, and Valley Way was unbroken when we started up early Friday morning. On Upper Valley Way we sank hip- to waste-deep *with snow shoes on*. In some sections, we had to clear snow in front of our chest with our hands and poles just to get a surface that our legs could reach up onto. We did this with 4 days' provisions for above treeline travel on our backs. Needless to say, our progress was slowed. We eventually made it to the hut, dropped our heavy stuff, and ran up and back down Madison. We started across towards Adams. The weather was forecast to improve in the evening with winds dramatically diminishing, so although we only had a couple hours' daylight left, we started towards Adams, figuring we could camp in Edmands Col. But the weather deteriorated. [Observatory had winds gusting to near 100 mph during this time]. We could see a snow plume blowing off the top of Adams and we were already pretty spent. So having barely set foot on Adams, and being nowhere near Sphinx Col, we turned back towards Madison and Valley Way and began looking for a protected spot to camp, hoping we wouldn't need to hoof it all the way back to Valley Way tentsite. We walked across Star Lake (a bit spooky with the weather doing what it was doing and knowing well the recent history of that spot) and found some decent-looking spots protected on one side by spruce. We dug in deep to get out of the wind, and got our tents set up (two tents of 2 people). The wind picked up dramatically during this time, and the spindrift was filling in our spot almost as quickly as we could dig it out. Eventually we got the tent set up, guyed it out using all 10 guy lines, and got inside, and it sounded like a freight train was running over us. I felt tremendous regret over not spending the extra half hour to find a more protected spot (i.e. Valley Way tentsite). It was COLD then, all of our water bottles were turning slushy, and we were spent. It was dark. There was spindrift filling my vestibule, as if a little hurricane was going off in there. So I pulled out both of my stoves and started to get my Whisperlite set up. There was so much snow blowing around in the vestibule that I didn't think I'd be able to get it primed. So I set it aside, pulled out my Reactor, plopped the fuel canister into a bowl of slushy water, and thankfully that lit right up, and in a few minutes we had our first boiling Nalgene to lift our spirits. Boy did that help. We got our sleeping bags nice and toasty warm, sealed up the vestibule a bit more with boots, packs, etc, trying to make sure we had SOME air flow, and continued melting snow. Eventually we got enough food and soup in us to be happy again. The wind raged and kept us awake and nervous half the night, fearing for the integrity of the tent, then everything went still around 1 am, then roared back to life at sunrise. [post script: we skirted Adams the next day but opted to bail before getting very far up Jefferson, seeing once again a heavy snow plume blowing off the top, and continued deteriorating weather.] I share this story only to emphasize the importance of having contingency plans and for acting on them when conditions warrant.
ChrisB- great story about Raymond Cataract. That spot is legend. It looks so innocuous from afar (and on the map), especially compared to the ravines on either side, but man, that has been the spot of many, many epics. Good on you for extracting yourselves out of that mess.