When an aircraft modification is developed it must be certified through the process of obtaining supplemental type certificate (STC). The STC will require whatever procedures, limitations, etc. that are deemed necessary for safe operation. For an STC covering power outlets, the potential for interference with the evacuation process would be considered an a restriction on use during taxi, takeoff, and landing would mitigate the threat.

A similar process was accomplished, though not as an STC, when each carrier modified their procedures to allow personal electronic device use during taxi, takeoff, and landing. That's where the two-pound limit and requirement for the PED to be secured or held came from.