Making someone a Friend is great; they show up on my Buddy List, and I'm notified when they log in. I like to be friendly and make new Friends, however, not everybody I like to talk to is welcome in my virtual bedroom.
I've run into several folks whose delightful hobby is to beFriend newbies so they can play virtual voyeur/stalker. They make use of the map's green dot functions to track when their quarry is with someone else. One virtual voyeur that I talked to became very confrontational; he opined that this behavior is acceptable and obviously condoned by Linden because "that's how they made the game."
It's poor reasoning to assume that anything that *can* be done in-game is therefore automatically 'good'. In Linden's defense, no online game can be held responsible for all player behavior. However, it's also true that SL's mechanics put the onus on me to prevent a fairly common bad behavior in a way that doesn't currently permit me to take a lesser action.
What if I'm very happy with my new friend-- I just don't want them to have 24/7 ability to track me? I must either bluntly ask them to always check in advance whether I'm indisposed (which is a minor nuisance too), or remove them from my Friends list, which will send a much stronger message than I intended.
A friend to whom I recommended the game has decided to quit because of her two experiences with cyber-voyeurs. She wasn't just embarassed, she was utterly outraged at the violation of her privacy. She said, "It's not just that this happened. It's that nobody has any ****ing way to make it stop." She said it felt like finding out toilet rims at the grocery store are equipped with cameras hooked up to the peep-show booths next door.
I was advised by another friend to "only make someone a Friend after I got to know them first". That doesn't work very well for me on SL. I find it somewhat necessary to beFriend somebody quite soon after we meet, else the only way I can IM them is by doing a Search for People- and I could only do that assuming I remembered their name.
So, my suggestion is this: Please, please, please make a This-Person-Can-Find-Me-Anytime radio-button for people on my IM list, and default it to OFF.