The crew was probably told they had some umbrella shield protecting them of media and friendly liberal politicians around the world who would come and save them in situations like this.
Sad thing is Greenpeace will treat these people like martyrs now and use them as recruiting propaganda for money and volunteers, and probably come out ahead in the long run.
They must have known Russia doesn’t play like that when it comes to State owned assets, and like the old saying goes - “When in Rome...”
There you go. To the Greenpeace executives, the stooges currently enjoying their soon-to-be extended stay in the Russian gulag are no more than sacrificial lambs "for the cause".