I tested the glass material in different environments. It looks like glass can be tinted per diffuse color if there is a skybox or horizon preset used. Rhino transparency color doesn't work.
If I set a dark environment per sun system and use a spot light, than the glass tint is gone.
Also I tried to get an air balloon look, I tried to make a plastic light transparent, but over 4% transparency I got a black material, if a spot light is used only. Per GI light it works better, but it looks like the transparency is without tint, the color tint is by the diffuse surface only.
Two other points - keyword "frosted" shows no effect and the light shadow of the semi transparent material is missing.
PS: Looks like I post enough for several days of reading, testing, fixing for the next weeks.