First we need someone with a out-of-state lion to get busted at the state line and then fight it.
My understanding is that SCI has, in the past, notified DFG that they were coming in with lion parts and told them when and where, and were never checked.
DFG knows that it would lose so choses not to fight it. It is a not enforceable. After that is overturned then it would take years of grass-roots working to get the tides turned so that lions were to be managed by the hunters instead of paid "professionals". However, given that hunting pigs and bears with dogs is on the verge of being gone forever in CA you are really just pissin in the wind...
I think that story is apocryphal. I first heard it at SCI right after the ban. It was always a vague rumor with no first-person accounts or names. Besides, plenty of people at DFG were pissed off at having management of the species stripped from them by a ballot initiative. I think they probably would have been willing to show up and make the citation or arrest. I think its more likely nobody in their right mind, especially a hunter, wanted to risk becoming a felon. (that's why I recommended Hatchet

)
The ban was enacted as a constitutional amendment via a ballot initiative so, it can't be challenged in CA courts. It would take passing another amendment repealing the ML ban or a 2/3 (3/4?) majority vote of the legislature and the Governor's signature to overturn it. I have been told that the import ban might be vulnerable in federal court, but who knows?
BTW, I don't think pigs are covered under the pending bill. Just cats and bears. Pigs didn't meet the cute-n-cuddly threshhold, but still, whenever they become a problem for the public, the bureaucracy or some conservancy, hunters are never allowed to be part of the solution. Apparently its moral to be paid to kill and maim animals with marginal weapons from helicopters and leave them to die and rot in the field, but if you are willing to hunt them fair chase for free (or pay for the privilege) because you enjoy the hunt and the meat, you're an immoral SOB.