That makes no sense at all.
People take chances based on the perception of risk. If there is a risk of getting caught, you are less likely to take a chance. If people are more aware that checks take place then you are increasing the perception of risk.
Many moons ago I used to occasionally jump the fare to where I worked. My entry station didn't have a barrier (still doesn't) and the destination was randomly checked. The second you heard there was a block on, you would stay on the train to the next station and then walk up the hill. What happens then is you pay for the fare because it becomes a place where you 'might' get caught. Because everyone knows this, you find that people tend to buy a ticket there because the risk is too great.
Not forgetting that those who do get caught will often get their details taken. If you become a serial offender, your pretty screwed and almost guaranteed to get prosecuted if caught again. If you get caught once, how likely are you to risk it again ? It's a bit like giving people speeding courses instead of points on their license. The theory again being that you are less likely to repeat offend.
The theory works. The publicity from this sting will spread and those caught will tell others. That WILL reduce fare evasion. If you look at how forumites have been posting that SE have barriers wide open all the time and no staff onboard checking tickets you can understand why that encourages fare evasion. Showing people that you might get caught, there are regular stings, there may be knife gates with BTP, there are onboard checks, regular blocks.. etc. again, WILL reduce that perception that its a free for all.
And even normally law-abiding folk will see there is no penalty and start wondering why they bother.
Assuming you're law abiding, do you wanna chance it ?