I personally believe this is unlikely, because then the firms paying for this data will not be so sure that the information is legitimate, whereas collecting directly from user devices makes fraud more difficult.
I could also imagine ways around that. For instance their proprietary SDK could generate the data and cryptographically sign it. Or they could require that app makers set up a special subdomain that points to their ip address. I guess it would only be worth the trouble if enough people care about it.
It is a genuinely tricky challenge from their perspective.