I think it blowing up or otherwise failing was probably the most likely case and they didn't really hide that fact, but I get the sense that they expected that

I think it blowing up or otherwise failing was probably the most likely case and they didn't really hide that fact, but I get the sense that they expected that it would make it a little further along, and not destroy the pad, such that the mess would end up in the ocean instead of on land. This is also littering of a sort, but it's also how every rocket stage pre-SpaceX has met its demise anyway, by design (except for the Chinese ones that seem to have a tendency to come down on land, often in populated areas). Dropping rocket parts in the ocean is just an accepted part of doing business, for better or worse.