But they didn't. Indeed, slightly more Arabs than Jews entered Mandatory Palestine between 1920 and 1948. The British let them come and go pretty much as they chose. Here is yet another article filling in some spaces.
https://r.search.yahoo.com/_ylt=AwriqXQf0mNltCYTIlgPxQt.;_ylu=Y29sbwNiZjEEcG9zAzIEdnRpZANMT0NVSTExNENfMQRzZWMDc3I-/RV=2/RE=1701069472/RO=10/RU=https%3a%2f%2fwww.jewishpress.com%2findepth%2fanalysis%2fthe-origins-of-arab-settlers-in-the-land-of-israel%2f2018%2f12%2f26%2f/RK=2/RS=4q7sSYyHdUHbXv5jqLGulYUMOZ0-