The fact that SBTPG is "working with the IRS" is a good sign. As I said earlier, in 2008 using refund transfer (RT) or RAL providers (like SBBT, now SBTPG) meant you got a paper check; but with RALs gone and even "refund advances" usually for less than the full refund, RT providers can actually help the IRS get the stimulus out faster than the Treasury's paper check printing facilities (even more limited now than in 2008).
IMO, the most likely solution will be for the IRS to send the money to SBTPG, then SBTPG will send it on to the customer just like a refund (hopefully at no extra charge). Even beyond TurboTax customers, it would work best for customers of other EROs who use RT but receive their money by other methods, such as an ERO-printed check or cash pickup at Walmart. (One of SBTPG's competitors even offers cryptocurrency as a refund option this year.) SBTPG sending its direct deposit info to the IRS might work for TurboTax customers, but not for these other people (and could easily violate financial privacy laws).
Something else to address a thread on the main forum: In this respect, the Turbo Card is no different from any other bank account or prepaid card. If you had no TurboTax fees (i.e., Free Edition) or paid them by credit or debit card upfront, the IRS sends your refund directly to your Turbo Card (using Green Dot Bank's routing number and your card's direct deposit account number) just like any other account; your stimulus money should be deposited the same way. (The Turbo Card's "ASAP Direct Deposit" feature, i.e., up to 2 days faster, should work for the stimulus check just like the refund check; same for other accounts offering early direct deposit.) However, if your fees were deducted from your refund, it went thru SBTPG (using Civista Bank's routing number and an SBTPG-generated account number); the handling of your stimulus check is TBA. You can look up the bank associated with your routing number at https://www.frbservices.org/EPaymentsDirectory/search.html .
Finally, the statute authorizes the IRS to send the stimulus money to ANY account of the taxpayer that received a Federal tax refund, benefit payment (SS/SSDI, RRB, SSI, VA, etc.), paycheck, retirement check, or certain vendor payments since January 1, 2018. Though 2017 returns and SSI/VA checks do *not* qualify you for the stimulus check, the IRS can use direct deposit info from those if necessary (as well as 2018 & 2019 returns and SS/SSDI/RRB checks which *do* qualify you). I would hope the IRS (possibly with help from SBTPG & other RT providers) uses the ACH network's "prenote" capability to detect closed accounts before sending money to them, but that remains to be seen.
