SS, thanks.
The finger wagging was stopped after somebody (allegedly?) was launched inadvertently while trying to swat a fly in the cockpit! After a national debate, it was agreed that the pilot should not accept the cable until ready to go, and having done so, launching is then at the signal of somebody outside the glider. The pilot still has a veto, of course, by virtue of the release knob.
Not only are there variations in law and techniques/practices between countries; there are some between clubs in the same country. For example, in the UK, it is generally the case that one pulls off an aerotow and turns left. Not at Cambridge, GC, however - they turn right. I am sure that there are other examples.