Jean's site has the answer. Duhh, shoulduh gone there fust! (as Amy would say)
David Hunter had a storyline with gambling addiction. Carney was just a bit concerned David would be drawn back into 'strip jack naked' (or whatever they play in such establishments).
I'm sure David's gambling story started when someone (a woman I think) grew suspicious that he was(as he had told her)going to the cinema alone,4 or 5 times a week.