I am trying to install skype in kubuntu 16.04. Following answer
(http://askubuntu.com/a/650808) requires me to update sources 
to include private 

abhishek@hp:/etc/apt$ cat sources.list | grep partner
## 'partner' repository.
# deb http://archive.canonical.com/ubuntu xenial partner
# deb-src http://archive.canonical.com/ubuntu xenial partner

1. Is it safe to do so ?
2.Why is private disabled by default?