Protection from what? Most people release their open-source work in the "just do whatever the f you want" spirit. If there is a commercial opportunity you can always re-license / offer paid support.
Protection from someone monitizing your work before you can monetize on it. If they get a copy of the code released under the BSD license, no amount of re-licensing will help get a penny.
In fact, many people will simply re-host re-licensed work, in an effort to keep the "free" version available.
In fact, many people will simply re-host re-licensed work, in an effort to keep the "free" version available.