From Section 3: Performance Timing of the adjudication handbook -
"3.03 A band is allowed a Performance time of 7 to 11 minutes anywhere on the Performance Field.
The timing will begin at the conclusion of the four-minute set-up/warm-up time, following the
announcement that “Bands of America is proud to present in preliminary/finals Performance
Drum Majors _____________ and ______________ and the _______________ H.S. Marching
‘nickname.’” If the first step or first note of music has not occurred within 30 seconds of
conclusion of the announcement, the timer will commence timing. Musical exits will be included
in the time of the show. Visual moves with percussion cadence (or silence) will generally be
included in the exit timing, and not in the time of the Performance.
3.04 Bands should completely vacate the Performance Field within two (2) minutes of the end of the
Performance. We define vacating the Performance Field as being outside/clear of the goal line (the
goal line being used for and in the direction of the exit) with all personnel, equipment and props.
Penalties shall be assessed only when it is determined by the Field Manager or Contest Director
that the band exiting is not making concerted efforts or substantial progress in complying with
the rule. Bands that “troop” the stands, exit the field in the wrong direction, or have props or
equipment that cannot be promptly removed will be penalized.
Any cadence/music used as an exit routine must cease once the Performance Field is vacated or
the goal line is crossed. We caution you to be conscious of the microphones, television cameras,
etc. while exiting. See also Section 6 below on Equipment & Restrictions."
and Section 4: Boundaries -
"4.01 The entire Performance including all music must be played from within the Performance Field.
Command personnel are exempt.
Drum majors may place and retrieve an instrument from any place in the Performance Area.
However, if a drum major performs on the instrument, the performance must occur from within
the boundaries of the Performance Field.
Exception
A student running a mixing board (i.e. balancing wireless microphones, etc.) may be located
outside the boundaries of the Performance Field, but in the Performance Area, without penalty.
4.02 All boundary lines are now included as part of the Performance Field. Stepping on a boundary
line DOES NOT constitute a violation. The crossing of these lines, defined as one entire foot of
a performer being placed “outside” of the boundary, will constitute a boundary violation.
4.03 PENALTY: For boundary violation – 0.1 points per flagrant infraction"
So maybe they are considering their tag ending as "exit cadence/music"? Or maybe they just don't care about it? Bands have definitely used this kind of ending before (i.e. Broken Arrow '05)
Hope that clears things up