Any GPS clock you are going to find in NY4 is going to be sufficiently sophisticated to check the GPS signal against its internal oscillator in order to check for validity. It can fall back to the internal oscillator if the GPS time looks bad.

The other reason this is unlikely to be a problem is that network time protocols break all the time (oops someone did a maintenance and broke sync with the master clock). Lots of real world trading code has sanity checks on the time.

It's the same problem. Assume my GPS clock is synced to actual GPS. You turn on your spoofer and now my clock sees that the GPS source is running faster or slower than it should be so it falls back to the internal oscillator.

Those GPS driven clocks would be marked as falsetickers and thrown out during the pruning process. I would hate to have my plan to create financial chaos blocked by the presence of one Symetricom box with a CDMA card and or off site clock associations.

Who needs a spoofer when you can make a jammer or emp? (don't do this, I have a friend of a friend story of a guy who did this in uni and got visited by men in black suits, the professor almost got fired)