In the classic \"RESTful Web Services\" book (O\'Reilly, ISBN 978-0-596-52926-0) it says on page 251 \"Some firewalls block HTTP PUT and DELETE but not POST.\"
Some 7 layer firewalls could analyze traffic to this degree. But I'm not sure how many places would configure them as such. You might check on serverfault.com to see how popular such a config might be (you could also always check with your IT staff)