Wow. This has been a long time coming.
I did a couple of quick searches on Austin venues of interest to me...
Stubb's - Blue sign. They've had the red signs up at the entrance for quite a long time, and I always questioned them. It's not a cheap venue for shows, it is all-ages, and they serve food. My suspicions have been verified.
La Zona Rosa - Red sign. Another one that I've wondered about. For the longest time they didn't post ANY signs. They're also all-ages, but do not serve food, at least as a restaurant. Their ticket prices aren't nearly as high, so I guess they make the cut to be above 51%.
The Broken Spoke - Red sign. Though they have a restaurant, it's primarily a dance hall, so I always wondered about the place. I guess I don't have to wonder any longer.
Spider House - Red sign. This one really surprises me. This place is a coffee shop that happens to sell alcoholic drinks. This honestly doesn't seem right to me. I haven't been in a while (guess I won't be going for a long while), so maybe the hipsters are drinking more Natural Light these days.
This tool is awesome!