My guess on the dlopen requirement would be somewhere in between. I have had success with the RB-libssh2 wrapper. It does not call dlopen.
However, reviewing the thread about the last time this RB-libvlc / Mac issue came up, I was only able to successfully get past the System.IsFunctionAvailable check. The declares / functions themselves did not work.
I suspect that if dlopen was used to load all of the VLC libraries it may have.