I can envision the situation of someone coming in with a fixed frequency wireless system, maybe they didn't coordinate around you like they should have and maybe any resulting problems are their fault, however that doesn't make it work any better or solve the problems. The point was really that a wireless solution will almost always represent additional work and potential problems that a simple cable from point A to point B would not.
The idea of coordinating frequency information on both sides is good practice, however trying to coordinate frequencies in advance has been a challenge recently with many having to change operating frequencies as new digital transmitters came on line last month and/or having to replace existing 698-806MHz units. Frequency coordination information provided a couple of months ago may have changed since then. So what happens if an outside group coordinated with the information you initially provided some time ago but you subsequently had to change something, is that still their responsibility? The reality is that in today's RF world things change and both sides should have some flexibility to adapt to the situation.