I do embed it in the metadata of the images. I have a profile setup in Lightroom used during import that populates certain fields with my business info, copyright info, and my FAA #. This, in combination with a Rights License I issue is proof that the images were legally acquired.
This is especially important for inspection imagery I do for legal cases.Lawyers are savvy enough now to get images used as evidence tossed out if they have no documentation of being legally acquired. I have a couple clients I regularly shoot for who use me because my images, and paper trail, are rock solid evidence in legal cases.