"We are talking about 2-3 decades in which to demonstrate a problem."
Correct. 1979 was the year in which it was agreed the 105 to 106 Mhz part of the band could be used by commercial radio stations from which the "fear" derives of possible interference. As I stated previously I understand there has not been a single reported case of such interference but the theoretical possibility exists. I am not sure how many stations actually use this part of the spectrum anyway but this gives a flavour
http://www.electricbluesclub.co.uk/u..._stations.html
Interesting that the whole of the USAF AWACS fleet was operating "with defective brakes" (non FM immune) until 1999 under certificates of exemption and only then ceased to do so becasue the EU refused to issue any more certificates.