This is the counterintuitive truth about crime:
1) The best way to make people obey laws is social pressure, not strict enforcement
2) In many cases, enforcing a minor law is more dangerous/expensive than letting it go
3) The punishment for a minor/moderate offense rarely has a positive effect on the criminal's future effect on society
So it sucks, and it's hard to get your head around it, and it's really hard for some "tough on crime" people to get their heads around it, but the best way to stop people from doing something bad is:
a) Make it illegal
b) Enforce it just enough and make the punishment just harsh enough that a reasonable person would know to stay clear
c) Make doing the bad thing a social taboo
I would never shoplift, and it's not because I'd get caught. I wouldn't. It's because there is a small risk I'd get caught and it would ruin my life, and because I'm not the "kind of person who shoplifts". I wouldn't try to sneak/force my way on the bus for the same reason.
The converse to all this is that you have to realize that some people will break the law and get away with it. They shouldn't get away with it. The guy who forced his way on the bus shouldn't get to ride the bus. He should be fined as well. But what are you going to do--make everyone sit there while you call the cops away from more important stuff? No, that's stupid. And if you don't do a good job on a)-c) above, people will start ignoring the law (like speeding). But if you do a good job, only a few people will break the law, they won't have a big effect, and it's more trouble than it's worth to stop them.
It sucks when someone gets away with something they shouldn't. It's unfair. But the people who commit most of these low-level crimes don't tend to have great or glamorous lives, so it's not like people will be "drawn" to that. On the other hand, overzealous enforcement tends to really hurt people and hurt communities.
It's always a balance, and it doesn't feel good, but this is the reason for all these "nonsensical" rules.