In many countries, such as in Russia, it was until recently possible to buy SIM cards which were not registered to a specific person. They were not even sold on the black market, but on regular public marketplaces in huge quantities.
True.
I don't think that passing the first level makes any sense for a gambling site.
If the user only deposit like, let's say, <$100 a month, it makes little sense to collect his personal data more than aforementioned lv1. What will he do with his <$100? Launder money? Yes, he can create multiple accounts but at the expense of a sim card, and sim card is traceable anyway, so law enforcers still can pinpoint his location.