there could be much conjecture regarding various scenarios

Indeed. Lets say the youth is telling the truth in that he bought a single for the outward and a single for the return journeys as it was cheaper to do so but the conductor at the start of his travels mistakenly issued two singles for the outward journey.

When he discovers this he realises that he has a problem but believes he can sort it out by explaining to the conductor on the return journey.

Like GSS above, this conductor knows he was "doing what lots of teenagers have done who have no money" so tells him that he a fare dodger and orders him off.

It is at this point he (OK wrongly) looses his cool. From his side the original mistake was not his fault and now on top of that, he being called a liar and a thief.


Of course the truth may be that he had only bought one ticket and that he was abusive even though he knew he was trying to dodge paying...