[WikiEN-l] Blocking of Tor exit nodes

[Open Phugu]

I have created an account, on en.wikipedia.org, from
a non-blocked IP. However, I am now using Tor, and almost
all the exit nodes are blocked.
Quoting from:
http://en.wikipedia.org/wiki/Wikipedia:Why_create_an_account%3F,
``Shared IP addresses such as school and company networks or
proxy servers are frequently blocked for vandalism which often affects
many innocent editors on the same network. However, registered
users in good standing can request existing blocks on their IP address
be modified to only affect anonymous editors so that they can continue
contributing to Wikipedia. ''

I have looked at the discussion on Tor open proxies
http://en.wikipedia.org/wiki/Wikipedia_talk:Blocking_policy,
and have several questions:
1. Can the blocking mechanism be set up to disallow anonymous
edits but allow edits from registered users?
2. Would blocking all the Tor exit nodes in the manner above cause
an increase in vandalism?

This policy of blocking edits from Tor exit nodes seems to contradict
several policies on Wikipedia: