Good point Steve, I would say it would have a marginal increase in the overall percentage, very few daily rail users would buy tickets on a daily basis.
I am all for having a better functioning station with people not getting away with fare dodging but they simply need to do it properly!! Not the half hearted way they have taken here! They need to extend the other entrance and insert barriers, they need a larger main station building to accomodate more barriers and space for people queuing for tickets.
All this costs money though so they would rather bodge the job and employ loads more staff to take the flack. tut tut Southern. (although they wash their hands soon enough, who thinks tfl will do a better job??...)