What a great question!

"Competent but not expert.." is reference to both ends of the scale.  It sets the minimum standard as 'competent' and stipulates that expert is beyond expectation.

To me, the interpretation of that minimum competency must be irrespective of age or level of competition.

There are a couple of reasons why I think this.

Competent? - Criterion, not norm.

There is one fixed standard to use.  Safety.

1.  The aim is to keep sailors safe.  To be safe, a sailor must, when faced with boat on boat situations, have the ability to adequately perform basic manoeuvres with sufficient speed as would be necessary to keep a race safe.

That is the common standard regardless of age or level or type of competition.

(We do not say that in the beginner / club fun beer can race that all sailors must be able to tack, but it's OK if people cant' gybe or judge a duck yet.  We don't allow double-handed sailors dispensations on Part 2 rules knowledge because they are double-handed.  These allowances would be unsafe.)

2.  Is it safe to give a bunch of first-day-on-water adults, small keel boats and let them race?  Of course not.  They would not be competent enough to in basic manoeuvres, and rules knowledge to be safe.  Can we give a bunch of the best 10 year olds a TP52?

What about the top end?  Do we hold experts at a higher standard.  This is interesting.

Technically, we should not. As I have mentioned, the standard of competency is not relative to the age or level.  The rules require us in ALL races to apply the level of 'competent, but not expert'.  We should resist the temptation to apply a higher standard in higher level events.

Imagine a pro expert taking part in a fun beer-can race.  Does he/she have to perform at the expert level?  We'll they are not getting paid...they may be feeling less prepared., under the weather.  They may be simply enjoying the day and not getting 'expertly' engaged.  You can't expect them to perform like an expert all the time.

What about at the class worlds?  This gets tricky.  Technically, we should not expect more.  In reality, I think it is natural to do so.

A holywood is really a match racing term for a great show, but may not be genuine.

@Lars - having done a number of WASZP events, I found the RRS 42 rules easy to see and enforce.

The world sailing judges manual changes on improper act or ommission in each version, each seeming giving judges more room for interpretation. Just track the change next time, it may be what gordon and i may expect.
The old bad race management hidden behind the word may not shall,, may not be tolerated.
A time of change perhaps! I believe for the better if we are to improve standards and improve the sport.

To me once a boat had done a 44.2 set of turns, they have not initially finished and there can be no other score but the last finish.

Other rule breaches are something else which really should be protested by boats.

There is no reason for a rc to act if they score the finish after the turns.