This is the reality of opening borders to nations who are still battling Covid. Pre testing will not stop the virus from being brought on island. The tests are not always accurate and or you can test positive after you have taken the initial test. With incubation lasting between 1 - 14+ days after exposure, there is no way of knowing how quickly it will spread on the island. If St Martin wants to start allowing tourism in, they need to ready their residents and medical facilities for a possible spike no matter what precautions they may be implementing.