Being Fashionably Late Has Been Fashionable for Some Time
These wood floors go back to before the turn of the century and were installed outdoors. Apparently if you were fashionably late to the opera house the sound of horse and carriage on the pavement was audible inside and caused a distraction.
Knowing that people would always be turning up fashionably late, these cobblestone wood floors were installed to deaden the sound of hoofs and carriages outside the opera thus making a late appearance less noticeable. So much for a grand entrance.