Thanks for your bug report. When I first added support for /omsg, /onotice, and /wallchops, many users asked me to limit their use to ops (due to the potential for spamming), even though they could have been made usable by non-ops (using mIRC's built-in implementation). So, in the same way, I have limited /vmsg, /vnotice, and /wallvoices to ops, under the assumption that these commands are primarily intended to be used by ops for channel management, off-channel user notifications, and so on.
In addition, it is not clear how different IRCds implement these features. For example, do all IRCds that support WALLVOICES allow any user, only + users, or both + and @ users to use it? (and perhaps +h helper users?)
So while I could make /vmsg, /vnotice, and /wallvoices usable by any user, only + users, +@ users (and perhaps +h helpers), or only @ users, I opted for the more conservative option of only @ users.
