Just wanted to get other peoples take on this. For a parent unit to pass along steadfast to its detachments it does need to be in combat, right?
Rather than us tell you or direct you to other threads where we argued about it at length, I'd be curious to know what your thoughts are regarding Steadfast and Detachments as a new player/poster.
Noght
p.s. You may already be tainted by Fidelis but still interested to hear....
As requested, here's my take on this...(please read the whole thing before firing off a rebuttal though)
To share steadfast the regimental unit needs to be in combat, because if you have no opponent to compare them to how can you say that you have more or less ranks.
However, I am of the camp saying that it doesn't need to be the same combat as the detachment. Can this lead to odd scenarios where the regimental unit is fighting something small and handing off steadfast to the detachment fighting a horde...yes, of course. Is this unrealistic though?...no, not really. The reason it's not unrealistic stems from how the regimental unit is "actually" passing on special rules to the detachment, namely the musician. Now I know not everyone pays for full command but "realistically" there would always be one.
The detachments need to be within close support (3") because they would need to be able to hear the musician relaying commands (special rules). The detachment doesn't behave the way it does because it can see what's happening but because it can hear it. Because of their training, when they hear rat-a-tat-tat (hold the line, we out number them) they don't look around going "Are you sure?" they trust in the message and do what they've trained to do.
As for the "timing issues" that people seem to have...I really don't think they matter. On my turn I pick the order of combat resolutions, and on my opponent's turn it's theirs. Maybe they'll want to resolve the detachment's combat first, hoping to get into the regimental unit's flank, or maybe they'll try to break the regiment first negating any support for the detachment. Neither is "more powerful" they're just different tactical options.
Warhammer is more about tactical positioning and playing to your stengths. If I can maintain my battleline and somehow force my opponent to meet me on my terms, then I should have an advantage and vice versa. If my opponent can out manuever me so that I can't utilize my strengths, then they get the advantage simple as that.
So there you go, my opinion. Was it hardcore RAW...of course not, did I make up new rules...no, just explained my interpretaion of the current ones using "real world" examples. Enjoy.