It certainly makes life easier for everyone if they do. I don't really expect that other people should be inconvenienced by my children's bedtime.
We're on holidays with my family at the moment. I can just put my boys to sleep in a spare bed/sofa wherever we are and they will go to sleep. Same with my cousin's children. My evenings are simpler than my SILS' who need quiet for bedtime.
Even if your family are all quiet for bedtime you will find that hotels, campsites etc can often be unexpectedly noisy.
When my boys were babies I vacuumed, talked on the phone, watched tv and other noisy stuff while they slept. I have never had cause to regret it. On the contrary, I'm quite glad my children are used to sleeping through noise.