all of 300.11 talks about support 'wires' and 300.11a1, fire-rated, says to tag the slack wires...
so i thot the idea of independent supports was to allow the electrical equipment to stay up there if the tiles and grid are dropped. limited energy guys use ties up there all the time, plenum rated if plenums, but we use the 12gage aircraft cable for our line voltage to support everything. and even though the MC section says you dont need support for the whips, we use them based on 300.11A, last sentence.
do fireguys cut the grid loose to drop it? is that the reason for tagging them?
anyway, my vote is to use the slack wires vs tie wraps