Student Finance Question - Overseas

I have a question regarding SF, especially to the students who have moved abroad. Is anyone actually paying back the loan? Let me elaborate.

I have heard from a lot of people who do 1 of 3 things.

1. They say they are unemployed in the online assessment and get away with it. I have never done it so I don't know if you need any documentation saying you are unemployed or what, but the amount of people who told me they do this and remain in their 3-4K (which in CEE where I live is massive payment) a month jobs is astounding.
2. They never contact SF, simply ignore everything from them. This one is especially funny to me because last year I did the same thing, however on accident and was given about GBP 500 in arreas on my loan which had to be repaid, otherwise I "would have to face consequences"
3. They go "self employed" and receive majority of their salary in cash, ensuring everything on payslips amounts to below the threshold (around GBP 16k a year in CEE).

Now I know there is a lot of fraud and issues going on with repayment of the SF from abroad (meaning: no one does it), but I am of the few who believe we should repay our debts, however I have noticed that SF is kind of making it harder for people who are repaying from abroad. E.g., the thresholds are too low, it is basically impossible to live off the rest. It really makes me angry especially because I know of so many people who got educated in the UK, show their shiny degrees back home but do not repay their debt to the UK government. Then there are people like me who do, but get screwed over.
How are these people not caught? I am not a vicious person and I do not mean bad to people, but this actually angers me because I try to be a good citizen even though I do not live in the UK or plan to even return, but I have friends and even collogues who tell me that there is nothing UK can do because they are not in the EU. Surely that's false right? I mean it is still a debt and I would assume a private company like SF would be able to handle a debt repayment even if coming from abroad.

What are your thoughts on this?

Thanks
jon