After finally solving 35 down, I started to fear for the future of crosswords: using 'It' as a synonym for 'S.A.' (sex appeal) is an outdated usage that only persists in crosswords; another egregious example is 'jolly' which was a nickname for a Royal Marine, a long, long time ago. I am sure solvers can think of many more ......
I can think of loads and have to say that I am rather fond of them after fifty odd years of solving. There's something appealing about the familiarity of hackneyed usages in puzzles. One of my favourites is "a bit of a kip" to signify AT. I'd be totally buggered if all references were to modern usages alone.