I tuned in to this movie right at the time liberace was watching people through binoculars. Not only can you see the people he's watching really well you can also HEAR them talking. I tuned right back out again. I usually don't mind little details like this but today I just did not feel like stretching my imagination.
He didn't hear through the binoculars, since he was deaf when watching them and was only reading their lips, the audience (us) had to know what they were saying. Its called advancing the plot.
When I first tuned in I did not know he was deaf at the time. I judged a bit too quickly and switched to another channel. I see now where it would have been necessary for the audience to "hear" what they were saying.