I use iPhone tethering with Mac OS X, and it all works fine. I prefer to use it over bluetooth only. However, when I plug in the cable, it automatically tethers (which is annoying as when I plug it in I only want to charge or sync - for tethering I prefer it to be explicit).
I would rather not turn tethering on and off on the network setting on the phone as that gets annoying.
Is there anyway I can ensure tethering only happens via bluetooth?