HAHAHAHAH SHEYN! I've created a monster.
Decent, i suppose they learn, but I guess there have to be logistical concerns. For instance, what if you don't have a bathroom attached to your bedroom, that's a HUGE problem. Creaking beds HAHAHAHAH, can be a huge problem. I'm so glad I don't live in a joint family system.
The other perspective is that of the parents. I wonder how many parents even consider this aspect of their childrens' lives, do they realize what is going on? I know too many people who complain that the parents are too intrusive and don't 'get it' that sometimes the husband and wife need alone time.
I lived for a year with my parents in law and never realized that they knew about us until the day I went to see my doctor along with my MIL, the doctor asked me few questioned which I answered and when she asked "when did you have sex last time" my MIL quickly replied "Last night".
Believe me that was the most embarrassing moment in my life.