As much as maybe fare evasion is a secondary concern, I think the main reason they're cracking down on the subways in NYC is because people weren't feeling safe on the trains anymore.
As much as I love a free and open and fair society, you can see why people not my size might be uncomfortable next to people growling, sleeping with trash bags filled with their belongings, drinking out of brown paper bags, rolling and smoking blunts and cigarettes. (I mostly bike these days but I saw all of that in recent subway trips during the early summer).
And then there was the rash of incidents on the subway with people getting shot at stations, the guy who tried to set off a smoke bomb and pulled out a gun on the car and started shooting, the guy who smeared shit on someone's face, the people who've been pushed onto tracks.
These incidents are _incredibly_ rare, but the way humans work doesn't let a lot of us shake off that perception of the subways being less safe than they used to be.
I'm not one of those people, I base my fears on statistics, but you can't expect every human being, especially smaller people, the elderly, and women to be as carefree.