I can think of one way to do this provided the user is willing to
double-click, but it would be quite involved, and it would also require the
user to download a template (not just a document) and to enable macros. All
of that is probably beyond your requirements, but here's the basic idea,
just in case:
A number of the fax cover sheets that shipped with earlier versions of Word
made extensive use of MacroButton fields. Most of these are MacroButton
NoMacro fields, which merely serve as overwritable fields for data entry
(with prompt text such as "Click here and type name"), but MacroButtons are
also used for clickable check boxes.
Unlike Check Box form fields (which require a document to be protected for
forms), these can be used in unprotected documents, but they do require the
use of AutoText entries and macros. The basic suite comprises two macros
(CheckIt and UnCheckIt) and two AutoText entries (CheckedBox and Unchecked
Box). The AutoText entries are just Wingdings characters. The macros swap
one for the other.
Although macros can be stored in documents (in Word 2010 the .docm format
would be required), AutoText entries can be stored only in templates, hence
the requirements stated above. If you have any further interest in this
approach (which could use ordinary, uncircled numbers and circled number
characters from Wingdings), see the article at
http://gregmaxey.mvps.org/Add_Toggle_Objects.htm.
--
Suzanne S. Barnhill
Microsoft MVP (Word)
Words into Type
Fairhope, Alabama USA
http://word.mvps.org