They're almost certainly provisioned with DEP, which fully automates installation of MDM tools even when the devices are wiped. As soon as the device reconnects

They're almost certainly provisioned with DEP, which fully automates installation of MDM tools even when the devices are wiped. As soon as the device reconnects to the Internet, it will phone home, load whatever MDM solution Apple almost certainly uses on their demo products, and will likely either wipe itself again or lock the device. The LTE-enabled devices will almost certainly have their IMEIs blacklisted by US carriers as well. Assuming Apple is following best practices for MDM on iOS and Mac OS, these devices are pretty much useless for anything but parts (and even then: the logic boards are still useless).