Is it okay to friend a friend's family members on facebook, even though she doesn't want me to?

[Cornmeal]

We're getting to be good friends and I've texted her sister before, but my friend didn't like me talking to her sister. I want to send a friend request to my friend's sister, but I know my friend won't be happy at all about it. Why are some people so private about this sort of stuff? What's the big deal? Should I do it even though it'll make her mad?

[.]

There could be many reasons for your friend not wanting you to 'friend' her sister. There may be things she doesn't want you talking to her sister about, or maybe she's afraid that you'll end up liking her sister more than you like her. In highschool I had a best friend who would talk to my sister a lot, and eventually started coming over to my house to hang out with my sister and sleep with my brother. If she's really your friend you'll realize she has her reasons and respect her wishes.

[Sue F]

If you want to keep your friendship, do not do things that will make her mad at you such as sending her sister a friend request.

It is obviously a big deal to her, and you should respect her wishes.