The full title of the session was:
- I don't know to which hotel I'm going to.
- From which country does a Lexus come from?
- For which party will you vote for?
Syntactic blends happen when people are unsure which structure to use. This often happens when there is a clash between formal and informal usage. The old rule was always - Never end a sentence with a preposition. This led to ludicrous and some tongue-in-cheek examples, such as Churchill's famous '...something up with which he would not put'!! This rule has left a legacy that an end-placed preposition is wrong, but natural speech makes it sound better, especially if it's a monosyllabic preposition that naturally goes after a verb to make a phrasal verb.