it's just always been the case of being class A
they acually have their own A.N.O (based on the UK ANO)
I would hazard a guess that it's because there are three airports with IFR Commercial traffic within a relativley small area
Jersey controls the Zone handing over to Guernsey who control the areas closer to Guernsey and Alderney
It's works ok, and SVFR traffic is always welcome and acommodated (even without a transponder if asked in advance nicely)
The limits are tighter for SVFR to take place than in the UK, but do you really want to fly when there is over half cloud cover at 500' or below and less than 3000m vis?
being based there for more than 8 years never really had any problems - you just get used to filing flight plans for everthing, and from a UK perpective you would have to anyway... as you are flying over an International Boundary and more than 50 miles from the coast
the only aircraft you are likley to see at light a/c level are the trislanders
and ATC are always top notch