Your responsibility to shield the password from prying eyes. After many years in IT I can nearly always tell a persons password by their fingers on the keyboard, not that I ever want to find it out. I've got better thing to do.
There are 10 types of people: those who understand binary and those who don't
The Password being visible onscreen on the Hub 3 is the last of your worries. Firstly changing it is not going to secure the hub from anyone who has physical access to it as all they can do it just use the Reset Pin hole and restore the default password thats printed both on the hub and the pull out card. Next if someone did manage to get software onto the PC to see the screen and see the passwords I would be more worried about the keyloggers that such software will also have to find your passwords even when masked on screen.
The Hub 3.0 is a Residential ONLY device and WILL NOT work on any of Virgin Media's Business Lines (I know for sure it won't as they tried to install one on my VMB line)
200Mb(SH2 SH2AC Hub 3.0), 2 X V6 TV XL, Phone M. 100Mb Business (Hitron Hub).