I've been openly in favour of installing the new BART style impenetrable fare gates all all elevated, underground, and as many other stations as possible.
They'd even work on the Valley Line for WEM, Mis, Davies, as you'd be stuck unless you paid there or rode to another stop. This would ease the burden on underground enforcement, increase revenue like what happened in Vancouver after they installed their bad fare gates
The wishes for enforcement come from a good place, but for some reason nobody ever checks for fares, especially after big events where they'd actually be able to find those who could pay the fines.