Also need to consider the safety of those persons if its a suspended ceiling with lift out or accessible tiles that persons my get entangled trying to access the void, or damage cables doing so. Although any suspended celing grid system the provider will design supports for weight load of luminaires etc, they may not have considered or known about all the cables lying on grid and their weight.

From my perspective its to be avoided and cables fixed to tray/basket suspended at a suitable height above the ceiling.

Cheers GTB 

Also need to consider the safety of those persons if its a suspended ceiling with lift out or accessible tiles that persons my get entangled trying to access the void, or damage cables doing so. Although any suspended celing grid system the provider will design supports for weight load of luminaires etc, they may not have considered or known about all the cables lying on grid and their weight.

From my perspective its to be avoided and cables fixed to tray/basket suspended at a suitable height above the ceiling.

Cheers GTB