That is much harder now; they now have to warn you when you reach your limit. See question 17 on https://ec.europa.eu/digital-single-market/en/faq/frequently...: "Therefore, as long as your operator has not contacted you while abroad, you can roam like at home without any worries."
So, they still can charge lots to those who, getting warned, don't immediately stop using their phone.
It is complicated because this is a political compromise. Everybody knows where the EU wants to end up (the frequent use of 'may' in that answer is a nice indicator), but that means shifting income of operators around (in general, operators in popular holiday countries lose a substantial source of income), so it can't happen in a Big Bang operation.
So, they still can charge lots to those who, getting warned, don't immediately stop using their phone.
It is complicated because this is a political compromise. Everybody knows where the EU wants to end up (the frequent use of 'may' in that answer is a nice indicator), but that means shifting income of operators around (in general, operators in popular holiday countries lose a substantial source of income), so it can't happen in a Big Bang operation.