Breaking hygiene with syntax-rules?

[Walter Lewis via General Guile related discussions <guile-user@gnu.org>]

Hi guile,

Consider this program:

(define-syntax unhygienic
   (syntax-rules ()
     ((_ the-pair fetch)
      (begin
        (define the-head (car the-pair))
        (define (fetch) the-head)))))

(unhygienic '(1) fetch1)
(unhygienic '(2) fetch2)

(fetch1)

;; => 2

It seems that the second call to unhygienic shadows the previous 
definition of the-head. I expected syntax-rules to generate fresh names 
for it each time.

Is this expected, and if so, is there any way to generate an internal 
definition using syntax-rules? For my case, I was writing a macro to 
generate SRFI-9 record definitions, but I noticed some of the getters 
and setters which I intended to be private were shadowing each other.

Best,

Walter