Это не так. Поменять тест на карантин может разрешить только врач на границе, а не само лицо.
"When you come from a country other than one with a low risk of COVID-19 and do not have a certificate of a negative COVID-19 test, proof of having had the disease or a vaccination certificate, you may be tested for COVID-19 in connection with a health examination. This
test is mandatory."
"When you come from a country other than one with a low risk of COVID-19 and you have a certificate of a test taken 72 hours before arrival, but no certificate proving prior illness or a COVID-19 vaccination course, you must apply for the test within 3 to 5 days (72 to 120 hours) of arriving in the country. This
test is mandatory."
"Please note that under the temporary amendments to the Communicable Diseases Act COVID-19
tests are mandatory on entry into Finland. Even if you are not referred to the tests, you are required to take them. The tests are free of charge. If you refuse to take a mandatory COVID-19 test and you are of age, you may be fined.
Please note that,
by decision of the communicable disease control physician and on the basis of individual assessment, you can be referred to a health examination or placed in isolation
or quarantine regardless of where you are arriving from and how old you are, if these measures are necessary to prevent the spread of the Sars-CoV-2 virus. "
https://thl.fi/en/web/infectious-di...s-pandemic#test