Try actually reading your Google hits instead of just counting them  Of the  unique hits for aluminum underwear  have nothing to do with shoplifting  directly concern the Colorado law and only seven generally concern shoplifting not specifically in reference to the Colorado law  Of the  unique hits for aluminum underpants  have nothing to do with shoplifting  reference the Colorado law and zero reference shoplifting in general  It is obvious from these Google results that the use of the phrase in either form did gain some popularity surrounding the passage of the Colorado law but disappeared shortly thereafter and did not fall into the general vernacular  Either form is therefore not ubiquitous and is inappropriate for this section title