"You can fool some of the spiders some of the time but not all of the spiders all of the time."
Collecting email addresses is a business, thus there are those that spend time figuring out ways to bypass email hiding techniques. I use the javascript technique on my pages (see http://www.jsnmp.com/contactus.html) and the associated JavaScript file.
Note that the latest scheme (I found this out on a job interview a McAfee) is to simply blast a domain with common user names and take out all of those that bounce. Thus, email names such as support, postmaster, webmaster, hostmaster, sales, joe.blow, jblow, etc. will always get spam.
jim