There are rules.

From the Cornish Pasty Association website:

ON THE INSIDE

Just good, wholesome ingredients, put together with love and care

Roughly diced or minced beef
Sliced or diced potato
Swede (turnip)
Onion
Seasoning to taste (mainly salt & pepper)
No meat other than beef, and no vegetables apart from those listed can be used in the filling. There must be at least 12.5% beef and 25% vegetables in the whole pasty. All the ingredients must be uncooked when the pasty is assembled and then slowly baked to develop all that famous Cornish pasty taste and succulence.

ON THE OUTSIDE

The pastry can be shortcrust, rough puff or puff, but it has to be savoury and able to withstand baking and handling without breaking. Pasties went down the mines, across the fields and out to sea, so they had to be up to the job. It can be glazed with egg, or milk, or both, to give the finished pasty its wonderful golden colour.

THE CRIMP

Here’s where the pasty comes into its own. Once it’s assembled, the edges are sealed by crimping them to one side, creating the characteristic Cornish pasty shape. If it’s not crimped, it’s not Cornish.

WHERE WAS IT BORN?

Any product sold using the Cornish pasty name must be produced west of the Tamar, in the wonderful county of Cornwall.

WHAT DOES
PGI STATUS MEAN?

SINCE 1993, THE EUROPEAN UNION (EU) HAS PROVIDED A FRAMEWORK THAT GIVES LEGAL PROTECTION FOR NAMED REGIONAL FOOD PRODUCTS AGAINST IMITATION ACROSS THE EU.

So, even if your aunt is sticking strictly to the rules, in Quebec she can only make a "Cornish" pasty, never a Cornish pasty. I know she's not in the EU, but I sincerely hope you won't be condoning a similar thing to what the yanks do when they call their fizzy wine "champagne." ;-)