There's nothing in the Terms of Service or EULA that says you cannot withold sending an action.
It is up to you on whether or not you want to use it.
This is true for a lot of the stuff that is extremely common on this site and the other boxing site too.
All of the GM Quotes, over all the years, have basically said: if everything that happens is a direct result of a key or mouse event, then you're ok.
If you can push something now, and have something happen later on that is not a result of something being pushed when the action occurs then that is botting.
Going by everything they have ever said to us, pushing a key and having it set to have nothing occur on that push, does not violate anything.
As always, use what you are comfortable with.
As an aside, there hasn't been a single GM quote anywhere that says it is ok to mouse broadcast.
So while we are likely ok with that, as a lot of people have been using it for some time now, use mouse broadcasting at your own risk.
Ditto for key remapping.
If you push a key, and it sends a different key to each window, that has never been okay'd.
It is ok to push "F" and have "F" go to every window, but there's no word on pushing "F" and sending "F", "Alt + F", and "J" to three windows.
So the entire two-step mapped keys, which people are running with both IS Boxer and HKN are not okay'd by any of the GM's.
Use them at your own risk.
Ditto for the entire FTL Assist Method.
You push the key, "F" for example.
Depending on the window you're in, it sends F+Alt, F+Ctrl, F+Shift, F+Alt+Ctrl etc.
However, you are not pushing Alt/Ctrl/Shift etc, you're only pushing "F".
So, while this has been around for years, it has never been okay'd.
Also the entire priority sequences for the Manifesto.
They have us push six buttons at once, all as the result of a single key push or release.
Blizzard specifically took Castrandom out of the game.
Yet our pseudo priority system essentially randomly clicks one of six things that is spammed.
Similarly Blizzard took Click Castsequences out, which has us mindlessly spam a single key.
And have a fairly intelligent DPS system result from that mindless spam.
They did not want mindless spam to result in an intelligent DPS result.
Yet that is exactly what we have, from mindless spam.
You can get that from IS Boxer and HKN.
Compared to getting around both Castrandom and the whole Click Castsequence Priority system for DPS, pressing a key and having it not send something to a window for a few seconds seems rather minor...