I think the first thing you need to do is make sure you have a good dress code policy. At this time of year, we usually distribute ours to employees reminding them of what is and is not acceptable. It's a good refresher. Our workplace is fairly casual and employees can wear jeans or shorts to work so long as they are in good condition, clean, etc. So, our rules may be a little less strict than others.
Basically, clothes must be clean and without holes. They must fit well. Employees should not show bear midriffs or backs, or wear clothes that are very low cut. While tank tops or sleeveless shirts are permitted, employees should not wear halter tops or tops with spaghetti straps. Shorts and skirts must not be any shorter than finger tip length when the person stands with his or her arms straight by his or her side. Gym wear is not permitted. While sandals are permitted, flip flops and other beach wear are not.
The policy states that at the discretion of management an employee who is not dressed appropriately will be asked to go home and change. Repeated violations will result in disciplinary action up to and including termination of employment.
We have a summer dress code as well, but our managers seem reluctant to enforce it, especially when it is hot out.
At your companies, do managers send inappropriately dressed employees to HR? For example, to get the logo T-shirts, or be cited for not following the dress code policy, or even sent home if the attire is extreme?
We banned flip-flops under safety, not the dress code. I must say I don't miss seeing employees' bare feet!
On Fridays in the summer, we are pretty loose about the dress code. So far, we haven't had to discipline anyone for too much "exposure."