Can Hong Kong people who are sued for debts in the Mainland return to Hong Kong?

No. According to relevant laws, if a debt is owed but still not fulfilled after a court judgment, the court will add the debtor to the list of defaulters and notify the immigration authorities to restrict his or her exit from the country. There are various ways to resolve such disputes, such as negotiation, mediation, arbitration and litigation, among which litigation is only one of them.