Extra-territoriality
Do national regulators enforce rules against entities operating abroad?

Hungary
Yes, but only if the services are considered as gambling services under the Gambling Act. The Gambling Supervisory Authority ('GSA') exercises its regulatory powers if (i) the gambling services covered by the Gambling Act are operated from the territory of Hungary, or (ii) the customer participates in such games in the territory of Hungary, or (iii) the service is aimed at customers living in the territory of Hungary, particularly when the service is made available in Hungarian, or if advertised in the territory of Hungary.
Accordingly, any enforcement risk against foreign operators seems rather low in the case of prize promotions, even if the prize promotion is regulated by the Hungarian Gambling Act (see regulations on prize draw below). At the same time prize promotions which are considered as gambling (contest of chance) (e.g. poker games, casino games, etc), are heavily regulated and enforced by the Hungarian GSA, including through actions against operators established abroad.
The Hungarian Competition Authority and the Consumer Protection Authority may also enforce consumer protection rules against entities operating abroad if the breach in connection with the prize promotion affects consumers in Hungary.