Almost 40 years ago now, I was on a visual recovery to Scampton one fine day in one of HMs' finest Vulcans after a short air test. Approach told us about a light aircraft in the vicinity....
Seeing it and approaching the MATZ, I announced "Tally the puddlejumper, QSY Tower".
Unfortunately, some Flying Prevention Branch trappers were around at the time and tried to raise a stink with my boss (Good old 'Sweaters' RIP) about gash RT - who simply replied "Did ATC understand? Yes. Well now say the same thing in correct terminology - in fewer words!". They couldn't - so he told them to Foxtrot Oscar as he had more important things to concern him. I never heard another word.
But yes, 'QSY' isn't correct RT.