Excellent point - I hadn't thought of that.
I can think of two solutions. The easy one would be to record your isos post-eq, although i feel that would violate their "safety-net" characteristic. The complicated theoretical way would be to use DSP equalization on set. The idea is that the location mixer and the post mixer share a piece of software that does two things:
1. performs realtime equalization on set applied after the iso tap.
2. stores metadata about the EQ on a track-by-track basis, so that post can mix from the isos while retaining the mixer's EQ decisions
Aaton has something like this, but only concerning fader movements. The Cantar mixer performs a mix during the recording, and the mix is described in the metadata of that recording. There is an application called Majax that takes care of the post end. Majax re-performs the mix from the metadata stored in the iso tracks, and is also capable of editing this metadata on the fly - you sort of get a second pass on the initial mix. The result is that post can use the mixer's mix as a foundation to which refinements are applied, rather than starting from scratch. I think that this is a kickass idea. Alas, I don't know of anyone who uses this workflow. Maybe it's big in France.
Anyway, it is a small step to get from logging mix metadata to logging EQ information.
The most likely candidate for this strategy would be Zaxcom, as they manufacture the only credible field recorder
featuring onboard DSP. The question is: are fader movements made on the Mix-12 recorded anywhere? My hunch is no.