In the past I was those network wall spammers and was making a killing simply by posting junk contents on the wall. Few months ago they removed the wall, since then I quitted spamming Fb and became one of their advertiser.

Back in the dark days I even rewrite (I am outsourcing this so someone does these grunt work MANUALLY for me) each spam post that I am going to post on each different network. I also rotate and randomly change the URL, of course IP address is also randomized. In the end it seems Facebook still manages to catch what I am doing although there are some days when their mods seem to be sleeping.

I've no idea about the friend adder that you are talking about, if it's automated ban then there's not much to do beside testing and learning their spam detection algorithm.