Actual conferences or events/get togehters ? Were they AVT focused? Were there a variety of ages or was it just little kids? If it was a little kid event, then no wonder there weren't 'terps. Most little kids who are oral first haven't learned ASL yet. But it is actually quite common for oral first kids to learn ASL as a second language. I know at the national conferences it's very common to see a variety of approaches used. I know for example, that even kids who can easily have a spoken conversation one on one, often find it difficult to have a conversation or learn in group situtions.
And there are many DODA families out there who use listening devices.
I dunno maybe in your area things are different. You really do seem to be expolarating with your experiance with your daughter's bi bi school, and assuming that represents ALL bi bi practice or ALL deaf culture or schools.