definitely highly illegal
I use bloomberg, and it's 1900$ / month, with a 2 year minimum contract and half price buy-out if you want to step back from the contract.
It's definitely not allowed to share a terminal...
The software is fixed to a computer or to a keyboard/fingerprint in the bloomberg anywhere solution. And I guess they have some sort of surveillance running in the background to detect possible sharing, vnc servers and so on...
I use my bloomberg terminal occassionally away as well through remote access and it works, but i really would be surprised if they didnt have any short of precaution to prevent this sort of behaviour in a big scale...