Does it Matter Which Ecosystem Participant Provides Zero-Rated Mobile Data Access?

Is zero rating of mobile data usage a violation of network netrality norms or only a marketing tactic? MIcrosoft India thinks it simply is a value of adding value for buyers of Lumina smartphones.

Microsoft India plans to sponsor 4G mobile data access for Bharti Airtel customers who buy Lumia 4G smartphones, though the deal is not finalized. As presently envisioned, buyers of Lumia devices will get use of twice as much data.

Airtel 4G customers purchasing the Lumia 950 or 950 XL will get free data bundled with the devices, as well as the  Lumia 550. 

Some would argue there is no difference between this proposed practice and the well-established practice whereby buyers of Kindle content can have that content delivered over some mobile networks without incurring any usage of a mobile data plan.

Nor, in principle, is this any different from promotions offered rather routinely by mobile service providers, where bonus data is provided for purchase of some plans, or for customers who switch from another provider.

In principle, does it matter whether it is an advertiser, a device supplier, an app provider or a mobile service provider that offers "no incremental charge" mobile data access?