Other signs that an educated diabetic spotter would look for are:
Flashing boobs when pump goes off when clipped to bra
Loitering in supermarket aisles squinting at labels printed in size 0.5 font to try and discover the carb content of a jaffa cake
Never letting the barman leave my sight so I can be sure he presses the Diet button on the drinks dispenser
Being unable to hide my fascination if I spot another diabetic out in the wild
The giant “D” tatooed to my forehead (well, it would be easier, it would save having to tell people)