I know this is an old article ... post ... but it kinda fits with my new one ... it just may be that this could be what Costco was trying to prevent ....
http://www.freerepublic.com/focus/news/1758390/posts?page=1
....just showing a valid reason for their policy...
came across while searching "Costco" making sure my article wasn't a repost ... made me chuckle
That is the one thing I hate about carrying.