This sounds like a subject where pedants of one brand or another could interpret the message as meaning almost anything.
I remember one day with such good visibilty ('bout 3 years ago) when as I climbed out of Goodwood I could see the BAT Tower at Woking and could thus have fairly legitimately said "Fairoaks in sight".
I rather doubt that would have helped me or anybody else too much as I had about 30 miles to go.
Surely the principle is that either :
you tell your FIS provider that you have your destination field in sight and therefore you would like to talk to them now so you can start getting acquainted with the visual circuit traffic you are going to join
or else
you are telling somebody with whom you already have contact that you have positivly identified the location of their airfield and thus have a fighting chance of crossing the right end of the runway (if that is your intention) or of identifying and avoiding traffic if it is described as being in a particular location (such as "short finals" or "in the climbout").
Isn't it about common sense and enhancing safety ?
DGG