As per What is the rationale for having the patent number as a tag? and Can patents be searchable by number? questions about specific patents should be tagged with USXXXXXXX
There are at least two problems with this
Currently the privileges are set at the beta level. If this ever changes you'll have to have 300 rep in order to add a new tag which means as the site's tagging won't work for new users as Ben Brocka noted
You can't do wildcard searches like US* because wildcard searches require at least 4 characters. This makes it difficult to find new Patent questions.
Please either remove these restrictions for [USXXXXX] tags or create a new field to hold the patent number.