Too Close for Comfort

The New York Times published an article yesterday about a buddhist couple living together with a few unorthodox stipulations:
1. Celibacy
2. No modern conveniences in their home
3. One must stay 15 feet within the other.

I kind of agree with the logic of the first two. I mean , if you don't have any modern conveniences in your home, having a child would be stinky and pretty unfun. Especially if you live 100 miles east of Tucson. Yuck-o. Diapers alone would be awful.

However I have a few questions for them:
1. Where does your water come from? I live in the desert. Water's pretty scarce. Do you purify it? Do you use a modern purifier for it? I'm interested in this system.
2. Why Tucson? Not to say that it's awful, but you could go about 200 miles north and it'd be a much nicer (and more inhabitable environ) for your purposes.
3. Why 15 feet? Why not 10 or 20? Where did 15 come from?

I am an awful judge of distance, so I measured out 15 feet. It's pretty close, but not as close as I originally thought it was (which turned out to be about 7 feet). But I think it's a little weird. What if she needs to go into a giant lady's public restroom? Does she choose the closest stall? Does she count the measurement out? I've been in some big public restrooms (seriously, Vegas? Who needs to relax in a public restroom armchair?) So I was wondering how stringently these two follow that last boundary. Is 15 just a guesstimate? "We stay 15-ish feet within each other" is what they should say in regards to accuracy. What if one needed surgery and the other had to stay outside the operating room? For purposes of sterilization of the O.R., it's probably a good idea for that person to stay outside any part of the procedure (especially if they don't have running water, ew).

I wonder if they tested out different distances to see which would work best. Did they use 20 feet for a week and then switch to 10? What was their deductive process?

If you had to stay any distance to a person, would you rather be super close, medium close or close-ish (like a mile or something)?