Aileen -- we have the same rule about not yelling for each other across the house!
Its a great rule. I myself tend to get caught breaking it the most though...
Sozobe -- I answered your post earlier and just discovered that my post vaporized. Weird.
Anyhow, the gist of my post was that I think it would be a heck of a lot more work (and its already a lot) to take care of my two kids without being able to hear them. (They are also 3.5 years apart.)
After I read your post, I realized that I *do* rely on my hearing a heck of a lot with my kids. In fact, I walked upstairs thinking about your post to pour a drink for my younger son, and had no sooner started when I heard my kids screaming at each other and could tell it was heading toward a volitile fight -- I wondered what would have happened if I had not heard and gone back down to intervene... who knows.
My 6 year old takes a bath by himself while I tend to the younger one. He makes little noises constantly in there, and splashes a bit -- if it gets very quiet for more than 2 mintues -- I go check on him. If I couldn't hear him -- I would feel like I should be in there -- and that would be hard with a younger one to care for, esp. because he now considers himself "too old" to share a bath with the younger one while I'm in there scrubbing them, etc..
There are probably a million situations a day like that -- the kids playing outside while I open a window to keep an ear out, etc..
Let me just say though -- that although it would be more work, I think it would still be doable -- and of course, I wouldn't give up either of my kids whatever challenges presented themselves. I think you probably know best about how hard it will be. Being harder to do does NOT meant that your kids would be at a higher risk. I think you would (and could) keep them safe.