On the CZ that seems to happen in DEN... but have learned that one has to pray that they don't make it worse - seems to be a 50/50 shot :-(On a couple of occasions I have seen a 2 man window cleaning crew, one with a sponge on a pole and the other with a squeegee give the Texas Eagle windows a quick once over in FTW.
Related: I assume that when they turn a train around, that they give the windows a good scrubbing - it seems that most of the time when I get on at SAC or DAV that they are pretty clean.