WBVA/5 is the "pseudo" call sign of WFXR/WJPR's "digital only" WB station. It's not a true call sign, in FCC terms, but it's just a branding that's being used in Roanoke/Lynchburg. They could call themselves "RKDN/5" for that matter, and there's nothing that the FCC could do - but folks know "stations start with a K or W", so starting with another letter might confuse the population (since the programming is broadcast over the air...)