>>>Michel,
>>>
>>>Note that I have 2 messages posted to Rick in the UT suggestions section. I created a message, posted it, clicked browser back button, changed the message and posted again. This created a duplicate message.
>>
>>Why wouldn't it?
>
>I thought there are techniques ( both cookie-based and cookieless ) that can prevent that (?)

You can prevent it, but there isn't an easy way to do it AFAIK. Sometimes you need to tell users to think first.