I feel like the name of this trope should be for something else, and the current trope description should be renamed to Leave It In. "Throw it in" implies someone came up with it more or less on purpose and asked, "Can we use it in the project?" and someone in charge said, "Sure, why not?" But "Leave it in" implies it happened without warning, and either nobody cared enough to remove it or they felt it should be left in, though it was never intended or even proposed in the first place.
The difference is that something thrown in was conceived of during production while not originally being intended, whereas something merely left in was entirely spontaneous and technically a mistake, added in the end but never discussed or even thought of before it happened.
Not to sound demanding or anything, and I know I know about notability, but are these actually real? Some I recognize but some seem excedingly unlikely...
Linking to a past Trope Repair Shop thread that dealt with this page: Split, started by Grobi on Jun 25th 2011 at 2:47:32 PM
"For a successful technology, reality must take precedence over public relations, for Nature cannot be fooled." - Richard Feynman