Thanks, that's a great list of possibilities! I did a bit of patching but also put in some new tubes... when I was patching I did find the small holes... I haven't been so careful to note the position of the tire when I take it off, to be able to infer where the pointy thing must have been or even still be, from the location of the hole in the tube. For sure I am very surprised to be getting flats all of a sudden... there is surely a cause! Hmmm, actually, when I took the old tires and tubes off today, I just left the tubes in the tires, so I preserved the connection... if I locate the leaks, I should be able to find the problem with the tires. Yeah, another surprising thing is to have the front and rear go leaky at the same time. Perhaps I rode through something really nasty. Those little bits of wire from truck tires, that's certainly possible. I don't remember riding anyplace out of my usual pattern, but then maybe a truck tire exploded out there somewhere and that's what did it. I do ride though a major trucking depot quite regularly!
I found a place selling those fancy Michelin inner tubes, at least they listed them for sale, so I ordered a few spares. Whether they'll actually get shipped.... we shall see!