Depending on the rules author's approach, rules tend to tell you either what you can do or what you can't do. The complex logic arises when these approaches are mixed with rules structured like "factor W applies against X except against Y in circumstance Z".
In the body of the rules many authors take care to make the meaning clear and unambiguous. However, the space restrictions of a quick reference sheet, and when rules are tabulated in the body of the rules, places a heavy emphasis on logical consistency, brevity and clarity. These three are very hard to achieve but are crucial in assisting readers to quickly assimilate the mass of detail required to play the game.
Let's look at a few examples from the Points of Advantage (POA) table on page 123 of the Field of Glory rulebook for Renaissance warfare:
- Impact foot / + POA / against any foot.
Rule  is a simple rule structured positively. Rule  is not so clear as the "against any" is so heavily qualified it becomes redundant and meaningless. Rule  reads as a negative list despite the positive phrasing. Rule  is complex because not only is it written as a false positive like rule  but the troop type is now qualified. Rule  is more complex still with a second troop type qualification. Stripping away the detail shows the inconsistent sentence (or row) logic:
- Type A has factor B against C.
- Type A has factor B except against Y.
- Type A, if X, has factor B expect against Y.
- Type A, unless X, if Y, has factor B against C.
- Type A, unless X, if Y, has factor B against C, except D.
When scanning the table the sentence (or row) logic switches back and forth. One row tells me what applies whilst the next tells me what doesn't. Furthermore restrictions and qualifications occur in three different columns of the table. I wished they'd all been phrased something like this:
- Impact foot / +POA / Not vs. mounted, Elephants.
- Heavy weapon / +POA / Not vs. Pike in >2 ranks, protected Shot, bayonet or impact Foot.
- Light lancers / +POA / Not vs Elephants, Battle Wagons, Heavy lancers, Pistols, non-charging and steady Spear, Pike, protected Shot or bayonet Foot / Only in open terrain.
- Pike in 4 ranks / +POA / Unless Fragmented or Severely Disordered / Only in open terrain
- Type A has factor B Not vs. C unless D only if E etc.
Sadly, these problems are not restricted to Field of Glory. Historically, rules have often been written this way. There's nothing on page 123 that looks unusual ,or untoward, to alert the authors to the problems. Put another way, the table fits well within the norms and conventions of wargames rules. Unfortunately, this is not a compliment.
Doubtless the restrictions arose during play testing and as the rules were tweaked and further refined to balance the game. Nothing wrong there; as long as everything is polished once the table of rules was finalised. I don't think this has happened with the examples above. Shame really as a review of the presentation to ensure consistency would really help the reader and encourage people to play the game.