Good grief - it was bad enough this evening (about 6.30pm) when they had a couple of people checking tickets at the PV exit; crowds of people waiting to get through.
Agree with pvp that it would be more sensible for them to install an Oyster scan point by the exit so prepay users can touch in and out, like the ones at DLR stations and at NX Gate. Preumably FH train users can't be trusted to do this themselves, though