Re: The future:
Have you ever ridden in a truly nasty cab? Now imagine that experience without being mitigated by the presence of another human being. The Internet has shown that people are less inhibited in their duchebaggery when there is not a person around to immediately judge them and they feel anonymous.
Much like people will spout vitriol in a forum or email (and even on social media, which has their name attached) that they would never consider saying in person, people will discard food/drinks/garbage in the floorboard of an autocab, and you will have people who take advantage of the "privacy" and leave behind traces of a more bodily type.
And after your ride is over you don't care for it. - This is actually the root of the problem; after your ride any mess in the autocab is "Somebody Else's Problem".