Hand, I’m sure the sign was turned on, but looking at the number of passengers on board, there were probably 40 people that ignored the sign or were walking around in the cabin. The 4 others were hurt by passengers and handluggage flying around in the cabin:D. the seat in front of you says: Keep seatbelt fastened when seatened. Why not do that? Why ignore the sign? Shouldn’t sleeping passengers be woken up if turbulence occurs?
About the strength of the turbulence, It’ll be very strong, with negative G-forces and all if 44 people are injured.