Reminds me of the time I packed two camera bags for a three-week road trip. At the end of the first day of travel (500 miles away from home), I realized I packed my camera bags, but they were empty. I had forgotten to fill them with actual camera gear! Luckily I always kept an old spare Nikon D200 with a 24mm f2.8 prime lens in the trunk of the car because that's the only camera I ended up having to use for that trip.
Man, back when I was playing music full time, I used to have dreams about showing up to a performance or an audition without my saxophone. Took a lot of years for that dream to go away even after I stopped playing.
I always double check my camera pack. And since I keep my main Pelican packed with both cameras all the time, it would be pretty hard to leave without them.