They say they don't check for speeding, yet they have full access to your OBD-II information, which definitely does include that. They could for instance easily add when you go over 85+ Mph which is the highest allowable speed in the US...

They might not be able to check on the location you are in to compare it to local speed limits, but they can definitely know if you are driving faster than the max.

I'm wondering how I can get one of these devices to play around with, without handing anything over but cash.