Wow, thanks DaT..  for getting me all paranoid.  I guess this is avoided in PoW by difficulty weighting.  In other words, if I say here take a look at my big chain 400,000 blocks also starting from the same satoshi genesis that I produced in 1 hour falsifying timestamps, this is longer than the current chain use me!   a node would say:  yeah great, but the difficulty was 0.001 the whole time that is not really a longer chain than our current BTC chain.  At least, I sure hope that's in the code.