If it doesn't come in a can, it isn't SPAM. (If it does come in a can, and it's Spam, it could be a submariner.) This is intended as a reassurance and warning: don't be fooled by dense meat-wads made fresh on location; only SPAM is commercially packed, slathered with cosmoline and packed in a tin.
A 12-ounce tin is a "distinguished main course for a formal dinner"? Only if everyone polished off a roast turkey before they came over.