Worrying? Wait till then get rid of those train captains and let it run fully on computer. Many systems alike to DLR have already done this, and it can be done if not the concern of vandalism (remember that the DLR stations are essentially open and unmanned like many national rail stations). That would be even funnier: hanging in between stations and no aid in sight...
(Once I was in Tokyo, my sister managed to leave her ticket at the ticket barrier, rendering her unable to exit the station as the only way to contact staff was through a speakerphone: my Japanese sucks and so as her English. However, after long deliberation, she let us off.)
I wonder though, with such a long wait at the station, won't it mess up all the other trains on the track?