As promised, here are my service notes:
28 PER SIB 12 15 12. CREATED PUMA CASE # ????????. PUMA WISHES
CUSTOMER TO DRIVE VEHICLE FOR A FEW MONTHS BEFORE MAKING SUCH A
REQUEST. NOTING THAT MSA IMPROVES FUEL ECONOMY AND REDUCES EMISSIONS.
UPDATED PUMA CASE. CUSTOMER REQUESTS THIS TO BE DONE. HOOKED UP FOR
VEHICLE PROGRAMMING. ENTERED IBOC CODE FOR NEW VEHICLE ORDER.
PROGRAMMED AS NEEDED INCLUDING CAS.
So yes, it is a BMW NA mandate to dealers: my dealer actually never hassled me about the request, and I only saw it on the service documentation after I picked up the car, so they would have no reason to make this note on the service record if it wasn't true.
IMO, BMW should accommodate customer requests related to this feature without the requirement to "live with it for a while". I think an apology is due from BMW NA to the community over this issue.