I just read your blog post and couldn't leave a comment there for whatever reason, so here goes.

Regarding interview attire, people ask because some teams are flip-flops and gym shorts casual while others wear suits every day. Wearing a suit to the flip-flops team interview is almost as bad as dressing down for the business formal team. Given the interviewee can't divine ahead of time with which type of team he's interviewing, the only safe thing to do is ask.