is not over (i.e., for multiple entry visas) and a form of being "out of status" and the offender may be fined, prosecuted, deported, or even blacklisted from entering the country again. Entering a country without a valid visa or visa exemption may result in detention and removal (deportation or exclusion) from the country. Undertaking activities that are not authorized by the status of entry (for example, working while possessing a non-worker tourist status) can result in the individual being deemed liable for deportation—commonly referred to as an illegal alien. Such violation is not a violation of a visa, despite the common misuse of the phrase, but a violation of status; hence the term "out of status". Even having a visa does not guarantee entry to the host country. The border crossing authorities make the final determination to allow entry, and may even cancel a visa at the border if the alien cannot demonstrate to their satisfaction that they will abide by the status their visa grants them. Some countries that do not require visas for short stays may require a long-stay visa for those who intend to apply for a residence permit. For example, the EU does not require a visa of citizens of many countries for stays under 90 days, but its member states require a long-stay visa of such citizens for longer stays. Visa extensions Many countries have a mechanism to allow the holder of a visa to apply to extend a visa. In Denmark, a visa holder can apply to the Danish Immigration Service for a Residence Permit after they have arrived in the country. In the United Kingdom, applications can be made to UK Visas and Immigration. In certain circumstances, it is impossible for the holder of the visa to do this, either because the country does not have a mechanism to prolong visas or, most likely, because the holder of the visa is using a short stay visa to live in a country. Visa run Some foreign visitors sometimes engage in what is known as a visa run: leaving a country—usually to a neighboring country—for a short period just before the permitted length of stay expires, then returning to the first country to get a new entry stamp in order to extend their stay ("reset the clock"). Despite the name, a visa run is usually done with a passport that can be used for