I only saw 1.5 like twice on Youtube, so I don't remember the proposal that much. But I remember not having much of a reaction. The main reasons behind this are:
1. A proposal is common in such comedies. If anything, I was wondering why 1.5 needed to go down such a clichéd path, instead of something more original.
2. 1.5 had already so many crazy scenes, that my expectations were nonexistent, and I honestly wasn't surprised by it. Mostly because of reason 1.