linuxdevices.com reports about OpenEZX. In that report, it quotes Motorola's chief architect of mobile devices: Motorola had no immediate plans to support native Linux applications on its phones, in part due to carrier concerns about network health, security, and interoperability..
This is just not true. In fact, the A780 as it ships in Germany comes with a native GPS navigation and routing application called "CoPilot". Also, since the whole GSM stack runs on a different CPU than the Linux OS, there are no security/interoperability/network health concerns that I could think of.
Also, I have received reports that Motorola actually distributes a Linux SDK to selected third party vendors. Parts of those SDK's (the header files for the EZX libraries) have actually leaked, which support the position that there is a SDK.
In many ways, the EZX phones are a combination of a traditional Neptune-based Motorola GSM phone, plus a Linux-based PDA. Therefore, if any native Linux apps on the PDA half could influence the 'network health' in a negative way, then any other Neptune based phone could, too.