by some sort of basic logic - everything that is not 1 key press = 1 ingame action is automatization of gameplay.

all macro's bruv... ALL

Combination keys like alt+c and alt+b to flag and lock/unlock BSR, I doubt are a big deal. Shift+x/z is probably grey area, most likely okay to do, but frowned upon.
If you use a macro to do any of these, it probably isn't okay, usually mice have their own seperate function for macros and combo keys.

Anything that uses a macro function like spamming R, always holding down a key until pressed again, chaining/doing skills, or anything of the sort, will probably be punishable.

Changing keys on your keyboard probably isn't an issue, but if you use a macro function to change it to certain keys, then it probably is an issue.

This^

Way back when, (using the minigame for horse catching as an example) one could be reasonably sure that you would be able to spam the space bar and catch a horse. Then, the mechanics changed to where you could not spam the space bar fast enough manually. Nobody could. Somebody "fixed" it supposedly, but it is still only possible for people who have extremely nimble fingers or those who don't care about their keyboard's space bar. People with arthritis or other joint issues must rely on some other means to win the minigame or give up "horsing" entirely.  I am hoping that PA is smart enough to look at why people are using macros in a specific area. If it's a rare thing to see a macro in a specific area, then it's on the player. If it's pretty common, as in horse catching (don't say it's not) then maybe it should be examined and tweaked to avoid the cause instead of punishing the result.

This sucks if that's the case. What about people who can't physically hit Shift Z and Shift X? 

I get banning someone for having a whole combo macro-ed. For example, [F -> left-click -> right-click] all programmed onto one key should be bannable.
However, simply hitting one keystroke for Shift Z or Shift X being bannable is downright ableist. It's not like those people will be able to compete in PvP or node wars anyway. They are casuals going at their own slow pace and using whatever they can to play the game.
Same with abilities like Shift Q. 
They can be set as buttons you can drag to your hotkeys anyway as ONE CLICK. So, what's the issue?

I stopped horse training entirely after they wanted us to sacrifice our keyboards and get carpal tunnel.
There is nothing exciting or engaging about spamming our spacebar. Just physical pain and fear of breaking keyboards.

A while back, I asked about the use of a macro for horse capturing. They had made it very diffficult for me to hit the spacebar fast enough and it was nearly impossible for me since I have neuropathy in my hands from transplant surgery. I simply wanted to use soomething that would allow the spacebar to repeat after a half second delay when pressed continuously, or bind to a mouse button. I was rather rudely told no. As a result, I gave up training as a life skill, after being unable to gather enough exp when I tried buying low level horses and training them to sell. I really miss it and I hope that someday they make capturing horses not as dependent on spamming the space key so much. I would take an rng component even, since that seems to arouse the devs. So now I have a shai that gathers and fishes and cooks and sighs as horses go by.