Ok. The one's I've used don't. That would be a good feature to look for, if you've decided on vest.jonnythan once bubbled...
I think I disagree. Most all jacket BC's have quick release buckles on the shoulder straps. Unclip them, open the cummerbund, and you're not at all attached to the BC anymore. In the case of a webbing harness, you need to either be able to slip downward out of it or have the room to remove your arms by rolling.