Oyster Barrier Tailgating

Oh dammit you silly rabbit.
A victimless crime is one without a victim..

There is no loss of utility to anyone in my test scenario.
The train is already going from Station A to Station B, the power consumption required to transport a single extra body is negligible, the cost of taking the payment would exceed the payment itself.

Agreed there is a high social cost as a perceived level of inequality or 'unfairness' is incurred;

Flawed.

The timetables and frequency of service are based on passenger numbers. Passenger numbers are counted by ticket sales and subsequent revenue.

Bendy buses were hugely overcrowded for years due to the fact that people took part in the victimless crime of boarding without paying a ticket.