[mschuster91]

Back then there was no lightning-fast international network other than horribly expensive international phone lines, no Internet, no tracking devices better known as cellphones, no national registries searchable in split-seconds. There were not many regulations on international transport as long as you had a decently forged passport. Additionally, there was a lot of support from e.g. church networks that helped out fleeing Nazis. Even the Mossad has its limits.