Because the initial reports said Jimmy Leeward and two others were killed; the dead count is up to eleven now, as parts were recovered and identified and some injured died in the hospital.
It may be time to consider the folks making extensive modifications (e.g. removing five feet from the wing and aileron segments) seem to be "winging it" without extensive testing and proofing, aeronautical engineering input, etc. enabling faster aircraft - and significantly increased pressures and stresses on remaining control surfaces they may not be designed to handle. "Galloping Ghost" is not the first highly modified P-51 to suffer similar loss of a trim tab, it seems.
One way to deal with this is to only allow old warbirds to compete as essentially stock / unmodified vintage warbirds, still interesting contests to be sure, but also more likely to preserve the few remaining warbirds out there as well as pilots' lives.