Do frum familes, almost all of whom have small children (or grandchildren visiting) actually use drinking utensils made of glass? For most people the shailoh will never arise.
There are some communities that do use glassware, and would allow having milk from it one meal, rinsing it out (but not kashering it), and then having chicken soup out of it. Most people would insist on not mixing milkig and fleishig utensils regardless of what they are made of.