Version:           0.70.0 (using 4.2.1 (KDE 4.2.1), Gentoo)
Compiler:          x86_64-pc-linux-gnu-gcc
OS:                Linux (x86_64) release 2.6.25-gentoo-r7-20080501

Kopete allows the user to only accept messages from people on the contact list (last I checked, GAIM refused to do that for ICQ because it might confuse spammers or friends familiar with the official ICQ client) but there's no similar provision for authorization requests.

Lately, I've been getting 2 to 6 authorization requests per day from spammers and I'm finding them very distracting and irritating. Since they're always different nicks, blacklisting would do no good. 

Here are some suggested methods for solving the problem:

1. Provide an "Accept authorization requests" checkbox in the preferences. Users who are bothered by such spam can either toggle it manually when giving out their contact info or always ask for the other person's nick instead. (Simplest to implement, but most inconvenient)

2. Allow the user to set services messages to expire after a certain amount of time. Combined with already extant support for disabling notifications, this would sweep unexpected requests under the rug while allowing expected ones through. (Of course, unexpected doesn't necessarily mean unwanted... especially if you're the type to give out your IM info when meeting people in person)

3. Like option 1, but instead, allow it to be added to the contact list window. (Less bothersome than option 1 for people who frequently gain friends)

4. Support authorization request whitelisting. (Like option 1, but compatible with swapping IM information in-person because you don't have to know when they're going to add you)