Because you don't know if they've done the trick. That's why natural language is padded with extra words to add context and help rule out misunderstandings. The grammatical rules of agreement are one mechanism to do this.
And you can see the phenomenon of over-abbreviation by reading a few debates on twitter and repeatedly seeing, "how can you not understand what I tweeted?!"
I remove semicolons from JS b/c I feel like they are a bit of a hack. Except where it's required by the language (for loops, which are becoming less used quite rapidly), your code generally shouldn't be so complex as to require semicolons for readability.
Having said that, I've been introducing a lot more colons, since I use TypeScript.
I was referring to punctuation that is, in some way, actually necessary. No one ends their lines with semicolons in python although it's valid. The rules when the interpreter will "insert" them are obvious. Not so in Javascript.
