No it doesn't. You're right. It does not give them the RIGHT to. Can I ask what watermarking is? I just opened legally a few months ago. Before then did it for family and friends. And do you have your pics photographed professionally or do you do it yourself? My photos need a lot of help. The backgrounds are horrid and distracting.
When you watermark a picture, it bears your name or logo on the picture so people know who made it and where it originated from. In the era of Pinterest, facebook, twitter etc where there are a thousand cakes out there by a thousand different cake designers, people know where to come if they want to see more of your work or purchase your cake. There's some free software out there to watermark your pictures - I've used the free picture editor at picmonkey.com. Just upload your picture by clicking Edit a Photo and on the left hand side choose the Text button and from there you can select a number of different writing styles (not sure about adding your logo). The size of the text can be adjusted and you can also fade it as not to take away from your masterpiece. Hope this helps :)