Keep in mind that announcements about the prerelease enable people to have a heads-up if you think it isn't stable. And no one is forced to update.
If you can setup an alpha testing group that would be ideal. If not, it still makes sense to offer things as soon as possible. The prereleases are meant for testing unstable stuff anyway, might as well actually do so and get more testing out of it.
Just give an instability rating on the announcement post.
