entry without a visa. Visa runs are frowned upon by immigration authorities as such acts may signify that the foreigner wishes to reside permanently and might also work in that country; purposes that visitors are prohibited from engaging in and usually require an immigrant visa or a work visa. Immigration officers may deny re-entry to visitors suspected of engaging in prohibited activities, especially when they have done repeated visa runs and have no evidence of spending reasonable time in their home countries or countries where they have the right to reside and work. To combat visa runs, some countries have limits on how long visitors can spend in the country without a visa, as well as how much time they have to stay out before "resetting the clock". For example, Schengen countries impose a maximum limit for visitors of 90 days in any 180-day period. Some countries do not "reset the clock" when a visitor comes back after visiting a neighboring country. For example, the United States does not give visitors a new period of stay when they come back from visiting Canada, Mexico, or the Caribbean; instead they are readmitted to the United States for the remaining days granted on their initial entry. Some other countries, e.g. Thailand, allow visitors who arrive by land from neighboring countries a shorter length of stay than those who arrive by air. In some cases, a visa run is necessary to activate new visas or change the immigration status of a person. An example would be leaving a country and then returning immediately to activate a newly issued work visa before a person can legally work. Visa refusal In general, an applicant may be refused a visa if they do not meet the requirements for admission or entry under that country's immigration laws. More specifically, a visa may be denied or refused when the applicant: has committed fraud, deception, or misrepresentation in his or her current application as well as in a previous application has obtained a criminal record, has been arrested, or has criminal charges pending is considered to be a threat to national security does not have a good moral character has previous visa/immigration violations (even if the violations did not happen in the country the applicant is seeking a visa for) had their previous visa application(s) or application for immigration benefits refused and cannot prove that the reasons for the