In fact, referring to page 16, I just recreated the diagram exactly as shown. Generator: function generator, 50 ohm source, 3m cable, signal pin to scope probe ground ring, probe set to 10x, scope set to 200mV/div.
Note, that's with the probe tip open circuit (this is justified below), clippy tip and ground clip removed. Just the coaxial pin and ring exposed.
I see about 20mV. The waveform shows it's approximately flat in bandwidth, probably either residual coupling from the open circuit tip, or actual leakage in the probe shield.
The signal amplitude by the way is 2.5V, so the shielding effectiveness is at least 40dB.
If I touch the probe tip pin, the signal becomes considerably stronger, and may become peaky as well. This is due to my body capacitance and resistance acting to ground the probe tip, at some frequencies or all, while the shield voltage moves independently of it. This proves that 1. the probe tip is moving with the shield when it's open-circuited, and 2. there is real, and substantial, voltage dropped across the probe shield, which does couple with the signal line within.
I sincerely hope that PowerPoint isn't based on a real book. I've heard loopy things about the Johnson book (but haven't reviewed it myself to see just how loopy it is), but this is just flat out, and very easily demonstrably, wrong, information.
Tim