The camera has no idea where you were standing in relation to your subject, it does however know what the focus distance was set to and has probably reported that accurately.
At those distances, even at f/2.8 there is quite a bit of depth of field, so you could have focused behind your subjects and still had them in reasonable focus.
I took some test shots under marginally controlled conditions. The camera remained in the same place on the tripod. Studio lights provided illumination of the papers. A remote shutter release was used but I did not bother with mirror lock-up. Rather than take clips out of the files, the whole file was converted to JPG and put up. Files are in the 10 Mb size range so if your connection is slow they may take a while to load. Keeping in mind that at the dot pitch of most monitors, viewing the file at 100% would require a monitor about 6 feet wide, the images all look OK to me. But, judge for yourself, share your thoughts.
Canon EF24-70mm f/2.8L USM, set to 43 mm. Focus distance reported as 3.2 m.
Canon EF16-35mm f/2.8L II USM, set to 35 mm. Focus distance reported as infinity. This view shows the whole end wall of my studio so you can see the setup. I used dental floss and tape to hold the newspapers.
Canon EF50mm f/1.8 II, focus distance not shown in EXIF data, probably due to non L lens.
Sigma 85mm f/1.4 EX DG HSM lens The papers were moved closer to the middle, so the lens could see them. Focus distance reported as 3.2 m.
Distance of 3.2 m is about right, a quick calculation says that is about 125 inches. A tapemeasure indicated 129 inches, which as they say is “close enough for government work”. The width of the backdrop frame, inside the uprights is 106 inches
A DOF calculator suggests a 43 mm focal length has a hyperfocal distance of 71.6 ft and focused at 58 feet the near limit would be 32 feet and the far limit would be 304 feet giving a depth of field of 272 feet, not exactly a small depth of field! You could park 4 tractor trailers end to end and still get them all into reasonable focus.
If you were thinking of saving money with f/4 glass, I would go for the 24-105 lens instead of 24-70, just because I always find 24-70 to be too short. The 24-105 is provided as the kit lens with the 5D Mk III. Having the lenses I do, I just purchased the body so I don’t have that lens.
For comparison, at 70 mm and 10 feet, f/2.8 has a DOF of 1 foot and f/4 increases DOF to 1.47 foot so it adds 5.6 inches.
Original 24 – 70 = 950 gr.
Mk II 24 – 70 = 805 gr.
24 – 105 = 670 gr., gives more focal length. But then, if you are in a dark church, f/2.8 is a stop faster, though not image stabilized. More shutter speed will stop faster subject motion, image stabilization will not.