Sounds like it'd be risky. Either it's small enough that it might come out while someone is drinking, posing a potential choking hazard, or it's big enough that people would need to open the can. Want to bet on what the accident rate would be for kids trying to cut open a can?
i think the US has some laws that forbid non-edible products being embedded in the middle of foodstuffs. IIRC that's the reason kinder surprise eggs are banned.
That's not inside the food. It's next to the food.
I suppose you could argue the same thing for this drink too, but I imagine it was just hard to get the spring loaded mechanism to be sterile and food safe.