This is very odd, and not the way I would assume it works. I will have to verify this. For you see, when I run "apt-get install anjuta" on the commandline (without Net::SSH::Perl), it does not require any interaction. We can see the output:

apt-get install anjuta
Reading Package Lists... Done
Building Dependency Tree... Done
The following NEW packages will be installed:
  anjuta 
0 packages upgraded, 1 newly installed, 0 to remove and 2  not upgrade
+d.
Need to get 2633kB of archives. After unpacking 6955kB will be used.
Get:1 http://ftp.us.debian.org stable/main anjuta 0.1.9-4 [2633kB]
Fetched 2633kB in 17s (155kB/s)                                       
+         
Selecting previously deselected package anjuta.
(Reading database ... 109891 files and directories currently installed
+.)
Unpacking anjuta (from .../anjuta_0.1.9-4_i386.deb) ...
Setting up anjuta (0.1.9-4) ...
[download]

I will try this again with a -y to see if it works differently.