Honestly, I've used the glass tanks as well as the racks with plastic tubs, and I've kept perfectly happy, healthy snakes in both. I've been keeping ball pythons in glass tanks since 2007 with absolutely no problems at all. Never a single RI, very rarely do I get a bad shed.

I know tons of people who've kept snakes in glass tanks for 20+ years. I think the importance of humidity is exaggerated among enthusiasts. Not to say it should be completely ignored, but frankly, in my experience, the only snakes that come down with RIs are the ones in extreme conditions, such as being housed directly in the path of a central heating vent or constantly being allowed to sit in spilled water. For the most part they're fine as long as they're not stressed. Sometimes people will change their snake's environment trying to act in its best interest, only to have it respond to the change by getting stressed and coming down with something.

Don't worry yourself too much over this. These little guys are a lot hardier than we give them credit for.