Putting someone in jail for breaking the law isn't about costs.
Besides before you know it nobody pays for their ticket and then what? This is a nice deterrent for any other sad sack who thinks he is above the rules.
It's also not clear to me that it is ethical to have a punishment be far more extreme than a crime. Sending someone to jail for 40 days for stealing $2.75 seems a little extreme. That could easily turn a poor person with a job into a homeless person with no job.
A fine feels more appropriate. Maybe free rides for those who legitimately can't afford the fare.
Before you say, not everyone can afford XYZ fine. I would fully support a income based proportional fine system in the US.
What i Don't support is putting someone in jail because they can't afford a lawyer.
With BART especially, you can watch the same person that jumped the gate light up a meth pipe in the back of the train car.
BART police will kick them off the train if they get caught but can't really do much else since the city doesn't really prosecute for drug offenses. If you look at the arrest records, you see the same people arrested day after day. They don't have any money.
I'd like to see a program that gives the option of jail or rehab+community service.
People tend to act like it is a given that a stricter penalty decreases the occurrence of the crime, but that isn't always the case.
No one is arguing there should be no deterrent at all. The argument is that the current punishment is too high and is well beyond being a reasonable deterrent.