- I was planning to do this myself when I got the time.

I see a few ways to interpret this…

1) The GNDT simply tracks YES/NO whether Musician X is playing an Insturment.  This interpretation doesn’t require Insturment to be otherwise defined.  Any Musician may change eir own “playing” from “NO” to “YES” and the Conductor may change anyone’s from “YES” to “NO”.

2) The GNDT tracks specific Insturments, where “Insturment” is implicitly defined by its use in this rule (i.e. something is an Insturment if it could possibly be inputted into the GNDT).  Any Musician may change eir own “playing” from “-” to anything at all, while the Conductor may change anyone’s to “-”.

3) The GNDT tracks specific Insturments, but for now, Insturment is undefined.

Could the author comment on eir intent?  If I were the enacting Section Leader, I’d like to know.

1 is out of the question by implication of the word “Single”. 

Why? “Is that Musician playing a single Instrument” is a yes/no question.

Perhaps the rule would be clearer if it spoke more of GNDT mechanics and explained the fantasy interpretation in italics.

This seems fine to me. The GNDT is just an external tool. The ruleset says nothing about how admins should deal with rules that add GNDT columns. The specific mechanics of tracking data in the GNDT need not be specified by rules.

It seems to me that the first proposed interpretation is out of the question because of the phrase “any Instrument”.

The second interpretation seems to naturally follow from the rule and the presence of an Instrument column in the GNDT.

I disagree with myself. The third makes sense, too, with other rules (e.g. ‘One is Enough’) implicitly creating Instruments.

If the second is intended, then , but just in case:

My <strike>Companion</strike> Instrument is Tengaar.

Is there a precedent for undefined Capitalized Terms?

Capitalization is almost always ignored, but I suppose it might serve as an indicator of the author’s intent in some cases when the author does not further specify eir intent.

Certainly, this rule treats “playing an Instrument” as a keyword (um… keyphrase?).  I also think the last sentence of the rule makes it seem as if “Instrument” is also a keyword (and would even if it were not capitalized).  Certainly, the Conductor does not have the authority to stop us from playing instruments, where “instruments” follows the normal English-usage of the word.

Maybe this was a bit vague - I meant the second interpretation, and I think the fact that the sentence says the instrument is tracked in the GNDT (rather than the fact of playing) backs this up.

It’s not a very strict wording, but given that the rule doesn’t do anything yet, there’s no difference between “yes/no” and “name-of-any-instrument/blank”. When someone adds mechanics to it, they can clarify the usage.