I was looking at STL - RNO on March 15th, (Sun) and there are ZERO Wanna Get Away fares available. It's as if they just blocked that entire day out. I've seen times where most of them were gone, especially close in, but not this far out.

The other Sundays still have availability.

I did check for STL - other cities (SAN / SNA) and those cities were almost gone. Maybe it's some type of unofficial start of Spring Break? But LAX and MCO still had plenty of availability. Go figure.