If you split T,T and get an ace, I would just be happy that you got a damn good hand instead of a stiff that can be busted or beaten. I wouldn't double down in that instance. Splitting 10s is one thing that will draw attention to you, and doubling on a X,A hand after splitting will likely cause a mild uproar in some places.
Also, when you split 10s and get a high value hand that most people don't hit, such as a 17-21, the dealer will most likely assume you want to stand and then just hit the other 10 with the first card. If you see it's another 10, then try to say you wanted to double your X,A hand knowing you would get a 10 for a doubled 21, you'll have an awkward situation on your hands...
If you have the guts or no heat, double the soft 21/11 against a 5-6 at true count of +8 (+/-1 depending on the system you use or book you read I would suppose), a 4 at +10 and so on. I've had this situation come to me a bunch of times and luckily not a second look from the pit. And just in case anyone was wondering, The index #'s came from my Masque casino game pak for the pc so there could be an error but they work for me. But since these happenings are rare, I wouldnt worry about it.
In Atlantic City, doubling down on an original 2 card 21 is forbidden.
I have never seen anyone split Faces - and then spike an ACE - and subsequently Double Down.
I am unsure as to how the pit would rule on that action.
However, I am quite sure that it will get you closely surveilled.
Of course in A. C. you cannot be 86'd -- BUT countermeasures WILL be taken against you.
I am "persona non grata" on the famed New Jersey boardwalk, being "half-shoed" or "bet restricted" -- at ALL stores.
In essence, what I am suggesting is that this cannot be a wise play as the actual monetary advantage to you (n real dollars) is miniscule -- even if you are spreading in Black.
"I have never seen anyone split Faces - and then spike an ACE - and subsequently Double Down.
I am unsure as to how the pit would rule on that action."
This play MUST be done when thew pit is busy elsewhere and I mean busy enough where they wont be called over. There have been many times where I didnt even split when they while watching or even at the table next to mine.
And where I play, the pit and dealers are mostly clueless. BTW, If I were playing in A.C. or Vegas, no way in hell would I attempt this play. Many noncounters split tens there and make all kinds of other rediculous plays which makes mine (when done at the right times) seem just as dumb as theirs.