iirc, military scans would show what was in a fleet, but doesnt actually say what fleet is inbound to you. I know, the early (R3) Mil scans did, but you had to forgo Hyperspace for those!
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As such, if anything, it would increase the amount of faking you could do; all you need to make sure is that your fleets have the same number of ships in them. But you have to do that now, i thought.