Yea, that is always going to be a concern with something like this, at the very least they have little incentive to try and take action against us.
We aren't competing with or affecting the user base of the Official Firefall (because they killed it and are no longer offering that service), currently we don't even require client modifications to make it work.
Everything we have gotten so far has been clean room reverse engineering, we haven't used any leaked code, essentially we are just making a server than happens to be compatible with Firefall.
We just want to restore service to and preserve a game that we were all invested in and even funded.
We're not trying to make any money of this either, in fact it is even costing us money
So "they" should have little valid reasons to try and take action against us. (not that it stops them from trying)