I sat down with one of the Electrical Engineers that I work with. He explained the practical information around this concern. Kemper when they designed the power section that is used to provide power to the Remote intended it to be used with the Cable provided. The Kemper cable is 22 AWG wire. This wire is larger than traditional ethernet cable which is normally 24 or 26. (The larger the number the smaller the diameter of the cable.) The smaller wire results in more resistance to the flow of energy on the wire. Therefore, if you use a standard ethernet wire of the same length as the kemper wire it is possible that you could experience problems with the remote. This would be due to insufficient power making it down the wire to the device because of the additional resistance of the wire. Kemper calculated the resistance of their wire and designed the power supply in the KPA to deliver the power over the 22 AWG wire. If you substitute the cable you are changing the resistance in the equation and you likely will get unexpected behavior.
The use of a POE (Power Over Ethernet) allows you to overcome the problem. The POE has its own power source which has been designed to provide the power over long run with the higher resistance wire. The power source on the POE is designed to be able to deliver the power over the long distance. You can then make use of standard ethernet cables for your long runs. I believe the POE specification indicates that you can connect a device up to 100 to 150 feet away.
I hope this helped. My comments here do not in any way intend to question anything that Kemper has done with the design of the Remote Interface. They designed the product according to their specifications and the product works as they intended. If we choose to use cables and distances that they did not intend then the problem ownership is our own not theirs.