I have been told bows are dry-fired to test them.
This is done in the factory and i dont think they will do it with every one bow that go' s out.
Bows should be able to be dry-fired although i would not like it to be one of mine.

In my friends shop we test limbs for cracks due to dry-fired shot or anything.
We use a very thin oil that sucks in the possible crack and after wiping the limb dry, the limb should not ' swet' oil.
I know there is something to test for hair cracks in alu and iron constructions.

This is it.
http://www.magnaflux.com/spotcheck.stm

I dont know if it would effect the material where limbs are made of.
Mabe someone else know?
Let me know.