I am thinking leashes for the elderly so they do not do a Bidet and wander off.
And it is not only the elderly that get left. This has happened before on other cruises.
A wrist tracker would have saved her life and saved them the time and money they had to expend turning around and coming back for her.
Just seems logical.
You would not do it at city stops just at scenic stops where there are no easily accessed accommodations.