Hmm, what about a Military Station (ship with no engine at all) and a Commercial "jump capable" Tug? What happens if a Tug attaches to a military engine ship, how does the "new" ship jump?
Will a tractor beam work through a jump point?
In VB Aurora, originally 'no engine' was treated as 'military engine'. It was changed to 'no engine = civilian engine' so that either type of jump engine could move one.
In C# Aurora,
if Steve maintained his programming logic, items default to commercial. Most likely 'no engine = commercial engine' but I haven't checked. If so, this would require a commercial jump engine to move such a station.
No, tractor beams don't "work" through a jump point, but since jumping doesn't require 'movement' it largely doesn't matter. Steve fixed the bug where jumping would automatically break tractor links, but since military jump drives can no longer jump commercial engines, you'll need to organize your sub-fleets by engine type if you want to do a squadron transit. Standard tranists ignore exactly which ship is where, because Standard Transits assume there's nothing within two hours to bother you.
Also, there's nothing about a Tug that requires it to have military or commercial engines, or that makes it a military or commercial vessel.
Also, also, the check follows the logic "is any of the forbidden thing present" so putting both military and commercial engines (or jump drives) on the same ship merely ensures that it can't jump at all.
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P.S.: Between VB Aurora and C# Aurora the terms 'civilian' and 'commercial' swapped meanings. A lot of people used them interchangeably to begin with, and some of us old timers don't always remember which way round it currently is.