First off, I want to commend you for your honesty.
Most people who get jailed categorically deny it.

Thank you for not lying.

Your jail is less than 5 hours long.

That's nothing.
Take this as your warning- it won't be so generous next time.

Given the right coding, even sparring could be macroed.

Macroing is impossible to avoid.
Especially for player jobs, since they're usually repetitive.

Even if the rocks randomly spawned, a macro could do an image search for those rocks, execute the mining commands until the rock is disappeared, then repeat the process to find another rock.

The only way to decrease the macroers would be to make the job more complex, as it would eliminate "newbie macroers" who don't know more advanced macroing.

And even then, it's not guaranteed.
People would eventually create macros for it, and distribute them.
The only guarantee that would come of making the job more complex is that the "legit" people would suffer.

We shouldn't have to make our game more difficult because of the bad apples.

Fortunately, as you have generously demonstrated, macroers are easy to catch.

I'd wager that you were caught because a player realized that you unresponsive, and were repeating the same actions (slamming away at a rock spawn point even when it's not there is pretty obvious).

That player then used the 'Report' tab, an admin warped to you to investigate, and when you remained unresponsive, you were jailed.

Hey man,
I did a 26 spar winning streak last night, on a trial account, with a Peacekeeper against mostly Repeating Rifles.

I had a blast.

Granted, that was in the Streak Spar room, where the walk speed is increased and you can dodge bullets, but still- I didn't pay a dime for it.

Distorted is absolutely correct.

If you had a simple macro that repeatedly presses the D button, not only were you absurdly obvious, but you were absurdly inefficient.

This limited you to one rock.
A good chunk of your macro's time was spent pounding away at the dirt, waiting for the rock to respawn.

Meanwhile, somebody with a brain (or a better macro) has no down-time.
Every time they complete a rock, they simply go to another one.