To avoid the extra spaces in submissions I use a Filter and RequestWrapper combination to trim all request parameter values. A submission of " " would get trimmed to "" and "88 " would get trimmed to "88". It really does the trick.
Note that my solution only takes care of leading and trailing spaces but the idea might help you to come up with a different kind of solution to the problem. [ October 25, 2005: Message edited by: Marc Peabody ]