(2a) Your parents are home. (2b) Are your parents home? (2c) *Are you parents are home?
No one would ever utter the (c) forms. No one would try to extract an auxiliary that isn’t really there. Those are clearly ungrammatical sentences in English. For everyone. The confusion between your and you’re is a spelling mistake. Plain and simple. Those words have really similar phonetic forms, and so people get confused about how to write them. Or they just have a “slip-of-the-fingers” when typing (cf. a “slip of the tongue”). But no one is fundamentally confused about it.
Now, I’m not saying it is therefore totally cool to just write whatever you like. Of course not. This kind of sloppiness suggests that the writer otherwise doesn’t care about detail or about the quality of her own work. I can maybe excuse one such mistake on an assignment or in formal correspondence (everyone screws up now and again), but too many and I start wondering.
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