In Blender, all instances don't use modifiers. In fact, only particles instances use a modifier.
Duplicating objects by using Alt-D instead of Shift-D create instances (shared mesh) not involving a modifier.
This kind of instances is very useful and necessary for repeated props incity scenes for example (street lights, balconies, windows, car wheels, detailed trees...). Exporting this kind of instances in Octane would solve most of the problems encountered with big scenes and would be very appreciated.
Particle instances are useful for grass, carpets, fur and large forest, but can be also done the same way by making real the particle system and converting the objects into shared meshes like done with Alt-D as well.
So, there is no more modifier at exporting time !
French Blender user - CPU : intel Quad QX9650 at 3GHz - 8GB of RAM - Windows 7 Pro 64 bits. Display GPU : GeForce GTX 480 (2 Samsung 2443BW-1920x1600 monitors). External GPUs : two EVGA GTX 580 3GB in a Cubix GPU-Xpander Pro 2. NVidia Driver : 368.22.