Haven't seen the horror aspect you're describing. The usual reaction I see is something like 'oh, your world has a TV show about me?' not 'i'm fictional AAAAAAAAAAAAAH', which when you're looking and multiverse stuff seems the more sensible reaction. Because they'd be real to themselves. It's different to meeting your creator.

I don't remember it being popular, either. Outside of DDD, which was pretty cracky, I can't recall it being common.

My feelings are different. In general, it's usually fairly boring. A quick, cheap laugh is the best it can get.