If anyone, such as SRM15, is having any doubts about this, don't worry. My friends and I are from the US and the code worked perfectly fine.

The process I encountered:

I checked out with paypal, went to retrieve the key and the code was locked due pending authorization via a link sent to my Paypal Email. I had to go into my email that is set up with paypal (since it was different from my GamesPlanet account email) and click a link that said "this purchase was authorized". After that, the code was still locked but only because I hadn't confirmed my GamesPlanet account (since I literally just signed up today). I went into my main email, clicked the link to confirm my account registration, and bam the code was unlocked and I was on my way.

After that, I just went to Uplay.com, downloaded the desktop client, and activated the game there.

I was so thoroughly surprised by these steps, in a good way. This site may be my new home for game keys! (sure beats sketchy places like G2A!)