Declined for reasons listed by AristosQueue in the comments thread. The specific comment is pasted here for convenience:
"So... I originally proposed this idea in 2009. In the time since then, I've been lobbied and debated by both sides. I think I have to concede the idea. It appears that structure nodes on the block diagram mentally serve as synchronization boundaries for a majority of users -- even if the job of the structure node is to comment out code. I have not done a scientific survey of this, but I definitely find more people who think it should sync than who don't. And that appears to be the same opinion heard by my peers on LV R&D.
The LabVIEW NXG development did discuss this question and decided to maintain the existing behavior.
I think it is time to close this idea as "Rejected." It's been discussed many times. I don't see it changing ever at this point."
Both the diagram disable structure and the conditional disable structure are intended to allow easy enabling or disabling of blocks of code. These nodes ought to have no effect on a diagram except to remove or add sections of diagram. But they currently have the side effect of formalizing the blocks of code they surround, as if they were a sequence structure. There are two cases where this is undesirable.
1. Without the disable structure, these two loops would run in parallel.
2. This VI arguably ought to terminate because that wire dependency from the loop to the Stop primitive is only created because whatever is in the disabled frame needs the result of the loop, but the code in the enabled frame does not. But because the disable structure acts as part of the code, this loop runs forever.