But what law says that everyone who starts learning to fly has to complete the course? People have different desires, ambitions, and finances - some want to be commercial pilots, some to be private pilots, some to just get the PPL in their hand, some just fly an aircraft solo once, some just take the controls once. Many of my trial lesson/air experience flight students are ecstatic at having actually experienced being in control of a helicopter (sort of!!!). Some of them are actually very good, and at the end of half an hour manage a gentle turn with the cyclic and fly us most of the way back to the airfield - and in an R22, that's not that easy. They go home having learned a lot, and whether they carry on is irrelevant to that fact.
That sounds an awful lot like a real lesson to me.