Would be pretty awesome, but as viet_boi says... could be another ignition episode.
If you are planning this, give a lot of notice and plan it well with big car parks etc. Also, make sure the roads you cruise on are fairly open, not lots of twisties, cause with that many cars, its not the bests idea. These huge events are more about checking out all the cars at the meet points rather than cruising I reckon. Would be good though