If you need an official statement, you most likely need to contact support.
Anyway, I'm not aware of issues with resizing virtual disks, if the guest OS supports it. The only exception that I'm currently aware of, is for cluster (e.g. MSFC) shared disks, which must not be expanded online.
The only issues with resizing that I'm aware of was with expanding virtual disks >2TB in vSphere 5.5, and 6.0.
André