Honestly I don't think that would be worth their time.
The LFLRV has three doors. If there was only one inspector I'd just go out one of the two doors without an inspector.
They could get around this by placing an inspector at every door (or using one door). But does it really make any sense to have three inspectors at the station to catch maybe one or two persons who boarded at the last stop that may or may not have paid. And then there's the problem with increased dwell and alighting times. Especially during rush hour I would imagine that the 150+ customers on the LFLRV would be quite irritated to have several minutes added onto their trip times because the TTC wanted to target a person who may or may not have boarded at the final stop without paying.
This problem should be eliminated when presto is implemented system wide. Inspectors should be able to check for payment anywhere on the system. But they'd have to give the passenger the benefit of the doubt with POP and time based transfers.