I've snuck into a Republican election night party or two (most of them are invite only, though loosely enforced). There's always a genuine pod people atmosphere that things will turn hostile the instant they discover you're not one of them.
You get the feeling at Democrat rallies that people would just look on in sad disappointment if some Republican pulled this.
That's pretty much my life as a liberal in Tennessee. When you think someone is too, it's like if you're gay and trying to feel someone out. I have to pick up on subtle hints, like someone mentioning healthcare without using the word "privilege". It's an art.