I'm sure that even if they weren't explicitly sharing the traffic information with Google then Google was capable of (roughly) inferring the data based on API c

I'm sure that even if they weren't explicitly sharing the traffic information with Google then Google was capable of (roughly) inferring the data based on API calls anyway. While there would certainly be some noise there between new tile fetches, you should be able to map out routes and speeds with a high (though not exact) level of confidence, particularly in cases where you're probably the one originally laying out the suggested route.