Crackerjack, you would think its not necessary but believe me when I say some people just don't know where to draw the line at "casual". I've actually had situations where I had to send people home to change their clothes.
Once it was a 30+ year old receptionist who had worked at a bank for many years so you would think she'd know what's appropriate and what's not. She showed up wearing shorts
and she just didn't see anything wrong with that. Another time it was an accounting executive, again older person with a lot of experience. She came into work wearing pijama pants - very cute but still pijama pants.
I find that when there is no written rule, people will push the boundaries to see how far they can go.
