[vouaobrasil]

Your assumption is incorrect, because the article doesn't say "the goal is to bond people who overstay their visa frequently." (quoted from you). It says (quoted from article):

"to impose bonds on visitors from countries with high rates of visa overstays"

Quite different, as the latter means it applies to people who don't overstay their visas, but who have a great many fellow citizens who overstay their visas.

[bediger4000]

So, guilt by association, a method known to cause unfair results. Now the only question is to decide why the bond was imposed on the countries it was. Who wants unfair results, and why?

[vouaobrasil]

I don't really think "fairness" matters to those who've imposed the bond. It's just a matter of economics, as always.