it could as well have been taken from
The Complete Guide to Rock Climbing (yet to be written) and it's a rather familiar experience if you're able to 'let go' and just do what you do (in no way restricted to music and sports).
But it has nothing at all to do with expertise - you'll forget about that anyway (so there's no need to intentionally deny it), but I can assure you that you'll appreciate any kind of sophistication you (already) have - it lets you get into the flow much easier.
One recognizes it only from a retrospective viewpoint, as in fact there's few to no concern (or even thoughts) while you're acting this way.
Ok, I climbed my first rock driven by an emotional impulse 'to just do it', far from any spectators and even farther from any knowledge, just driven by instinct.
It was RIGHT at that moment, but it could have cost my life.
I wasn't completely naive and the view downwards clearly revealed the consequences of a mistake - but for some reason it didn't strike emotionally, it only increased attention.
This has been confirmed by others as well - it either works THIS way or you panic and die.
The point is... you do not know your reaction in advance
In a musical context there is (fortunately) less potential to physically damage to your health...
Yet some sophistication in handling your instrument will help greately to avoid this drift away from the flow.
To stay with the example - it wouldn't cost your life, but possibly your career
On the other hand this type of 'flow' is what happens anyway if people play and get along - no matter which music or audience.
So there are few reasons to point it out specifically or set yourself in an artificially restricted 'beginners mode'.
cheers, Tom