Of course, in truth, I wouldn't use the quotes here for anything except "San Antonio."
[ ~dog star ]
as any high-frequency synonym would probably be in an incorrect context.
After a fairly extensive measurements of this effect, it became clear that in most real use cases, the net interpretation with the ~ included in the query was not really what the searcher thought they were getting. In fact, it was actually damaging most queries with ~ in it. (How do we know this? A: By running experiments... lots and lots of experiments asking people to rate the quality of the results from searches with the tilde, and without the tilde. It wasn't even close.)