heres the best way to avoid ninja.........
attacking fleet in route..with 7 mins till attack send probe at 10% speed or try to make them arrive around same time as attacking fleet...then send 1 probe with attacking fleet on acs mission then slow probe down...this will slow fleet down by 1 or 2 mins allowing ur probes to pass attacking fleet and arrive 1 or 2 mins before attack...no more ninjas....
feel free to post ur knowledge here...i hopw i explained it good enough..any questions im me