TBF, I was boosting my own toons (5 wow accounts under 1 bnet account) and I didn't get banned. 11 twink full screen on one monitor, other 4 on second monitor. I used WowOpenBox to place / control the windows. The toons on follow use a macro to follow me that I stick on a button bound to a mouse button, so I just hover over that window and click it. And I used the macro to get past the XP eliminated debuff. I also had an addon (not a weakaura) that would auto accept both the invite and the role check. But I clicked enter dungeon manually.
As for my twinks, they are semi BiS (I had the neck with 3 gems, I had the waist, shoulders, and chest with sockets/gems). I ran the two SL gems for speed and HP regen. I run at 149% (though since I took my toons with me (for loot reasons) and didn't leave them at the beginning, isn't gaining me a lot, I have to constantly stop for them to catch up).
I never did any of the other things you can do while farming gear on your twink to increase my drop rates or to reset the instance. I just ran in, killed, ran out, reset. I did this mostly while at work, so there were forced breaks already which worked out well, I never once hit the 10 per hour limit.
Also for clarity, my toons were on follow, and I made sure they didn't go AFK, and that they looted each boss (click on window, loot boss, click follow macro). I leveled 100+ toons from 70+ to 80 this way. The biggest pain was the amount of time it takes for a queue to pop when you queue with an XP off character.
For me, going forward I will be using a level 70 on another bnet account (I have multiple bnet accounts, all have same info (name, address, billing, etc.) for RAF reasons over the years), as even while I was safe in this pass, the risk isn't worth it anymore, and the level 70 I have is geared enough that the time per run is near the same (especially since I bring my toons with me and don't leave them at the entrance, it's not geared out for speed, it was just a toon that got KSM in DF S4 and has the leggo). And the best thing, the queues pop instantly with the 70 (as XP isn't off, the toon is max level). And my 70 toon also isn't a Demon hunter, and I won't be doing any of the fly through walls to last boss and kill it in 20 seconds like I have read in other threads is possible.