Used Airtel for 1.5 years, never received any promotional call.
Using Tata Play since 2018, have been asked if I want to take any one service channel (not of my choice ,whichever they were offering ) but only if I had placed a request for technician visit either for any issue or after upgrade.
After technician successful visit, Tata Play called for feedback & then asked me politely (or I would say try to sell) if I want that one service channel at a discounted price for 1st month, have to say NO for 3-4 times to reject that offer.
But without consent they never added any service channel.
Maybe they started this offering within last 1 year , not always but only after technician visit.