It's getting more difficult to argue against playing "trick the computer" games, when IRS itself is suggesting it with the 1099-K problem.  But you wouldn't tell someone who received a $20,000 gift to add it in and then subtract it out, even though it's being reported on a Form 709.  (We don't know for sure that they don't use those for audit leads, do we?)  My concern would be how FTB would view this when it has a different place on its forms for showing the exclusion.  If you're sure it's not a concern, then go ahead and increase the taxpayer's gross income when you don't know if some legislation is going to give an importance to that number that is not obvious now.  

Exclusions should not be added to income only to subtract them out.  Stay away from that slippery slope.