First off, I am not Pro nor Con on the subject as it relates to the OP, However I would like to address this. When I play by hand I use a ton of Macros, including Mouseover Macros, especially when I am playing a DOT class so your argument that a "Normal player" would not spread Multiples DOT's without ever selecting a Target is invalid to me. Also I have similar Macros(ingame) paired with Macros(Keyboard/mouse) that treat "Aimable spells (Blizzard/Heroic Leap...ect)" as basically a cast at mouse location spell, which again weakens your argument. Finally there are plenty of "Whackamole" type addons out there that Highlight exactly what spell to cast, which buff to refresh and a general laundry list of what to do next that this cannot be a legitimate tool for weeding us out.
Now as it relates to the OP "Is HB detected?", well technically speaking the answer is Yes, anytime someone is Banned HB was in some manor "Detected", either by reports, scripts, or manual investigation. I believe what you mean by detected is that Blizzard can see the HB process running on all of our machines instantly with the flip of a switch. While the latter is up for debate I believe it to be highly unlikely (not impossible). my opinions are just that...Opinions, but here is why I doubt that Blizz can see us all whenever they want.
1. The age old argument that we would "All be banned", while I have my own feelings on wether Blizz would actually Ban all of us at once if they could see us, the truth remains that if they could see us all then they would likely rid themselves of us eventually. (I know its a pretty weak argument)
2. I suspect that if they could see us all that they would use it as a tool to make money and not simply ban us all at once, but rather roll out Bans in waves in order to keep enough people coming back to keep the machine rolling while demonstrating to the "ban all bots" user that they are making an effort. If this were the case though I don't believe you would see certain activities scoring quicker bans than others. it would just be random selection groups of folks using HB.
3.Based on my personal experience and having watched/participated in these forums for many years (old account that dates back well before the shown start date of this forums account) that many of the things that we accept as generally true are that Player reports are largely responsible for many of our bans. That Blizz certainly uses auto ban scripts as it relates to Time, Kills, Gold... and many others (I don't believe it is any one thing, rather a combination of things that draws a flag), and that GMs can personally investigate an account and determine fairly accurately if someone was Botting.
Now for my speculation: If these recent reports are true and that people are actually being Banned for simply using CR's and an "Enyo" type Botbases then perhaps something is afoot. I do know that I can often times spot certain "Bottish" behaviors in raid groups. Things like Auto-Buffing the entire group every time someone joins or leaves the raid, re-buffing every time you swap out a piece of gear or talent, instant group buffs upon entering the raid, tossing out random heals while the group is standing idle waiting to fill or explaining a pull, insta interrupts.....The list goes on. I believe in pressing stop on my bot to ensure that it does absolutely nothing out of combat, I handle all of my major CD's (See Shammy popping lust the millisecond a boss is tagged, or Pally popping wings and hammering away on an immune target), my own interrupts, and buffs. Disable instant Battle rez and many more like this as I think they are dead giveaways. Maybe this is all ther is to it and could explain why my accounts are alive (knock on wood) and others are not.
Now put on your tinfoil hats and take a walk on the wild side. I have often speculated or wondered if the CR is not what is giving us away. We know for a fact (given the World of logs, and other such sites) that Blizz already has in place the ability to track every spell cast, every step, and every nose pick completed in the game, and exactly when each of these actions occurred. Based on these suspicions I started sorrting through a Metric Shit ton of logs and started noticing disturbing trends. After looking at my own personal (Warcraft logs) i began noticing trends in spells cast, the order in which they are cast, and the timing of those casts. When I compare them to logs from other players they usually are not nearly as linear...yes they are similar but I started picking up on exactly how precise the routines are compared to playing by hand. If I can see this with the naked eye, I am pretty sure that Blizz can write a script to pick up on this.
I think that routines should "Mess up" randomly and randomize the timing of spells cast (I'm talking Milliseconds here not timing that would cripple the CR" among other things. I think in our search for the perfect rotation that we are exposing ourselves to others. Nearly every CR executes on opening combination the exact way on every mob it touches, the same order, the same speed between casts and so on. No human player Always selects the exact same order of spells, every single time and with the exact same timing between button presses. I admit that again this is speculation, but I think it is food for thought from the Devs.
Thanks for reading my long winded post if in fact you have.