I thought it was a little underwhelming.
Do people really mistake a stretch with a play bow? I very much doubt that's a common thing. I suppose it might be easy enough to mistake it in a still picture, but the energy is so different in motion that I'm not sure she was arguing against anything real for that first section.
The part about creating distance was a bit more interesting, but certainly for most interactions I see, a play bow (yup, still going to call it that

) is an invitation to chase, which I include in "play" when it's consensual between all parties. Even watching the video of the bowing in the interaction between her collie and the GR, I would consider that very much a game, even though there was no contact between them and only occurred in brief spurts.
I do think it can be easier to mistake it with a herding dog stalk, for those collies who throw themselves onto the ground with a lot of energy, but even so, the eyes and tail generally give it away. There's a very different intensity between the loose and floppy body language of a dog who is wanting to interact and one who is in a prey sequence.
There is one other type of movement which I have seen which might come under the same heading, and that's a stiff-legged "bow", where the dog stays quite upright and stiff when they're doing it. It's akin to a person taking a fast and heavy stomp forwards to scare off a critter. Again, the body language is very different and, whilst some of the mechanics are the same, no-one would ever confuse one for the other.
A play bow is a bow. There are other types of bow. It doesn't mean we shouldn't still call a play bow by that name. As she said earlier on, we have different words for "smile" to differentiate between something friendly and a smirk. To call them all just a "smile" would be to withhold information. So surely by the same note, calling a play bow just a bow means we're doing just that, withholding information. If we're sure it's an invitation to play, whatever form that play might take, then why not call a spade a shovel?