If you make opening locks a zero-stress spell, à la flickum bickus, you can just say goodbye to any locked doors in your game ever.
I'd make it a 1-Stress Rote. That way, they have to ask themselves whether it's worth casting or not. Otherwise, they'll just be opening every door in every corridor they ever encounter, just to see what's inside - like smashing crates in video games!
Even though the Rote doesn't require a roll to control the magic, you could still require a roll to represent manipulating the tumblers, etc.. That way locks can be Aspected with things like "shoddy" or "Swiss manufactured" or whatever, and provide varying levels of challenge to open.
EDIT: It is important to keep a cost associated with opening locked doors. Let's say you have a game where opening locked doors is a zero-stress, no-roll spell like flickum bickus. Now, all doors are effectively unlocked. An unlocked door is a barrier only by convention. That is, unlocked doors are barriers to polite people. Which means that it might as well not be there at all.
Sidebar: What About Blocked Doors?
Now sure, you could have doors jammed shut with wedges (or pennies) or barricaded with furniture or boarded over or whatever. But none of those would fall to any "unlocking" spell anyway, so let's leave them out of the picture.
One of the comments complains about the lack of "realism." Realism is:
A) Overrated in gaming, and
B) Not what FATE is about
FATE is about story not reality. Here's a piece of supporting evidence: Go read this example of combat in FATE. Now, when Bonnie puts "blinded" on her opponent, she gets to tag it once for free. But she has to spend a FATE point to invoke it a second time. That's because an Aspect is not a situational modifier, it's a piece of fiction that can be used when it's important to the story. If FATE were modeling reality, once Bonnie blinded that guy, he'd be subject to appropriate penalties until he got better by whatever mechanism, and Bonnie wouldn't have to spend metagame currency to create narrative significance.
The comment says, "...there are doors, and there are locks- that's just the way of the world..." Right. And there are cars on the street and there are tiles on the hallway floor, and birds in the trees, and planes in the sky. You're not going to stat each of those out, or even mention them in more than passing unless they're important to the story.
So what I'm saying is that when you have a locked door, you're asserting that it's important to the story. And if it's important to the story, then the PCs should have a meaningful decision to make - "Do I spend a Stress point to unlock this door or do I try to pick it manually, or do I try to break it down, or do we blow it open..."
With the free unlocking spell, there's no question. Just unlock the door and move on. No story. No decision. You might as well have a roll against a target of -12. Even with a zero skill and a roll of -4, you're going to succeed. So you're just wasting time.