Mike,

Your friend might be worried about the solvent soaking into the material.
I think this has been discussed on lml before.

When bonding to either fiberglass or carbon I no longer clean with
solvent as the last step
before the bond.

I do sand carefully before bonding.  Then, having just exposed fresh
material, I believe solvent can only do harm, carrying oils onto the
surface.

-Jeff LNC2 N273CK, still building