I noticed since some time that whiskey offered in offices of bosses in US movies or series often tend to be poured from anonymous glass bottles/decanters. I saw this often happen in House of Cards for example. I remember Frank saying once something about a blend in an early episode.
Is keeping whiskey in glass bottles an American culture thing or has this to do with some laws what type of alcohol can be "advertised"/plugged in movies?
If it is a culture thing. Why would you go through the trouble of pouring whiskey from one bottle into another one? Are people really mixing "home-made" blends?