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Should I use the __block specifier on an object pointer, even if it works without it?

I use a completion block CAAnimation(using CAAnimationBlocks ) to provide processing at the end of the animation and part of this completion block changes the animated CALayer. This works even if it is layernot declared using a qualifier __block, since the pointer of the object remains constant, however, I really consider the object as read / write.

One aspect of the Apple Guide that bothers me:

__ Block variables live in a repository that is shared between the lexical region of the variable and all declared blocks and block copies or created within the lexical region of variables.

Given that it layeris a collection iterator that looks like it really will break if I use the specifier __block.

Here is the code in question:

for (CALayer *layer in _myLayers)   // _myLayers is an ivar of the containing object
{
    CAAnimationGroup *group = ...;
    ...
    group.completion = ^(BOOL finished)
    {
        [CATransaction begin];
        [CATransaction setValue:(id)kCFBooleanTrue
                         forKey:kCATransactionDisableActions];
        layer.position = [self _findPosition];
        [CATransaction commit];

        [layer removeAnimationForKey:@"teleportEffect"];
    };

    [layer addAnimation:group forKey:@"teleportEffect"];
}

My real question is: I am doing it right (my spider feeling is tingling).

EDIT I should also add that my application uses MRR, however there is no saving / releasing problem if the layers are static in nature (their lifetime is the content NSView). I also seem to be doing exactly what the Templates, in order to avoid the manual section , say that I should not have done, although it is not clear (to me) why.

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EDIT:

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