Connect to users terminal useing `screen`

[RedBar0n]

Hi List,   I'm trying to monitor my user, I'm testing "screen".   I can connect to the same user (if I started screen for user foo and then I login in a second session as foo I can connect to the first foo session), but this thing can't work if I "su - foo" ( I get an error "Cannot open your terminal '/dev/pts/0' - please check" , prs/0 is my current tty), so I changing the permission to "777" on this device, but I believe that there is more elegant way to do this ( connect to user session as root without "su, chmod 777 /dev/pst/XXX etc...)   P.S if there is more efficient/secure way to monitor users and help them, please advise me :-) Thanks, Gili