Well you say that, but they clearly didn't to begin with.
Jeff looked to be over 10 feet away. When they saw the problems, one read from the manual, misquoted the 9+ feet maximum for the play area as being the maximum distance you can sit, guesstimated that was probably about what they had, shrugged and carried on.
It was only when a viewer pointed out the FAQ states 5 feet is optimal and the 9.x feet figure was supposed to be the play area limit that the tape measure came out and the distance to camera put right for both setups. Their issues were definitely mitigated after this. They did not disappear, nobody is claiming that, but there wasn't nearly as much weird z-bobbing.
Another way they didn't follow the instructions was standing up, leaning forwards and reaching out to calibrate a Move, then moving back, sitting down and expecting that was going to be good enough. That should have been a big red flag that the camera distance was not correct, really simple stuff to pick up on.
Definitely. When they enjoy something, you don't have trouble seeing that, they don't just draw their joy from shitting on crappy games for example.