Well, that seems to be the case. If, when they (the authorities) find an illegal and they can't find any document which proves their (the illegal's) country of origin, they can't send them to a detention centre while they're prepared for deportation, they have to be released but are supposed to report to a police station at regular intervals but what happens then is they just disappear.

The process is then repeated if they're found again but the next time they're then charged with failing to report. If they're bailed again, they just clear off again.

When first found, the reason they're "illegal" is because they can't produce any document proving that they entered the country legally.