It has changed in the last year.
For example, the 2005 Rule for Hobie 16's was:
4.4 Each mast shall have a black band around it, as
supplied by the HOBIE CAT CO., to indicate
a) The black band is located 24 ft. 8 in. (7.52)
meters) from the top of the mast not including
the mast cap.
b) The uppermost portion of the gooseneck
slide shall be the guide for measurement,
and the top of the slide must not be downhauled
beyond the top of the band.
The new 2006 rule was changed to eliminate the downhaul restriction:
4.4 Each mast shall have a warning label around it,
as supplied by the HOBIE CAT CO. The warning
label shall be located below the opening in
the mast track.
With the new 6:1 downhauls on the 16, you can easily get the slide past the black band now.