I was asking about the Subscription plugin, because Pidgin should show Authorization request, when someone wants to add you to their roster. So, adding is not silent. At least, shouldn’t be. I see such requests in Pidgin 2.7.1.
As for the main “issue”. This is just how XMPP works. If you try to add someone, he has to approve this and you both are added to each other rosters. If someone decides to delete your contact, he is also removing your subscription to his presence information. I have tested with 3 clients and all of them behave the same. No notification about removing. Though, if your client is offline when someone deletes you from his roster, then his contact won’t disappear from your roster when you get online. But this contact will stay offline all the time.
As i read http://xmpp.org/extensions/xep-0162.html i see that clients are recommended to have more options while deleting contacts. But user who is deleting the contact still has a prerogative not to leave his presence information available for the user which contact is being deleted.