Not from my home, but I have stayed at Cabana Bay since VB first opened and had my Cabana bay resort ID checked many times. Unless they have changed something more recently, it used to say dedicated Cabana Bay resort guest entrance or something like that. It was a great perk of staying there. Last time I walked from Aventura on their path and had a much longer security line. I will be at Aventura in Sept and will walk over to check it out, it is a lot shorter security line. If it has changed they certainly don't advertise it.
Googling, other websites also think this -
touring plans "Volcano Bay has a dedicated entrance just for Cabana Bay guests!"
uriversalorlandoguide - If you're staying at Cabana Bay and want to visit Universal's Volcano Bay water park, you'll have the option of using a private entrance to the parks.