Triple the fines, and the poorer people who may have paid up before won't be able to anymore. It's a delicate balance; otherwise it would be too easy ("just make the fines $10 000")
What do you mean? Why were they evading the fare in the first place?
Tripling the fine may decrease the number of people that pay it, but it would also essentially shutdown the group that encourages people to skip fares.
or adopt something similar to the UK's penalty fare system, which generally allows innocent mistakes to be dealt with with a minor fine, whilst persistent offenders end up with a potentially large fine (upto £1000) and a criminal record:
Unless you're rich, in which case you can just get off by paying the original ticket price, and avoid a criminal record altogether [1]. By punishing innocent mistakes, and mainly operating outside rush-hour, the UK penalty system unfairly targets tourists, the elderly, and anyone else who is unfamiliar with the nuances of all the various rules, prices, etc. It also treats honest citizens like dirt and is wholly regressive and outdated in my opinion.
People slip up, forget to renew the pass. There are multiple reasons why large fines will have the exact opposite effect, and only make it much harder for those already poor. It's easy being well established to swallow a fine like that, not so much when you live out of what you made that day.
You could however take the group to court, from my point of view this is organised fraud.