diff --git a/app/models/draft.rb b/app/models/draft.rb
index a2fba62fe50..2165a0ad8a2 100644
--- a/app/models/draft.rb
+++ b/app/models/draft.rb
@@ -10,6 +10,8 @@ class Draft < ActiveRecord::Base
   class OutOfSequence < StandardError; end
 
   def self.set(user, key, sequence, data, owner = nil)
+    return 0 if !User.human_user_id?(user.id)
+
     if SiteSetting.backup_drafts_to_pm_length > 0 && SiteSetting.backup_drafts_to_pm_length < data.length
       backup_draft(user, key, sequence, data)
     end
@@ -94,6 +96,7 @@ class Draft < ActiveRecord::Base
   end
 
   def self.get(user, key, sequence)
+    return if !user || !user.id || !User.human_user_id?(user.id)
 
     opts = {
       user_id: user.id,
@@ -128,6 +131,8 @@ class Draft < ActiveRecord::Base
   end
 
   def self.clear(user, key, sequence)
+    return if !user || !user.id || !User.human_user_id?(user.id)
+
     current_sequence = DraftSequence.current(user, key)
 
     # bad caller is a reason to complain
diff --git a/app/models/draft_sequence.rb b/app/models/draft_sequence.rb
index 681a8bcb2ef..b79f3c92567 100644
--- a/app/models/draft_sequence.rb
+++ b/app/models/draft_sequence.rb
@@ -2,10 +2,12 @@
 
 class DraftSequence < ActiveRecord::Base
   def self.next!(user, key)
+    return nil if !user
+
     user_id = user
     user_id = user.id unless user.is_a?(Integer)
 
-    return 0 if invalid_user_id?(user_id)
+    return 0 if !User.human_user_id?(user_id)
 
     h = { user_id: user_id, draft_key: key }
     c = DraftSequence.find_by(h)
@@ -18,27 +20,17 @@ class DraftSequence < ActiveRecord::Base
   end
 
   def self.current(user, key)
-    return nil unless user
+    return nil if !user
 
     user_id = user
     user_id = user.id unless user.is_a?(Integer)
 
-    return 0 if invalid_user_id?(user_id)
+    return 0 if !User.human_user_id?(user_id)
 
     # perf critical path
     r, _ = DB.query_single('select sequence from draft_sequences where user_id = ? and draft_key = ?', user_id, key)
     r.to_i
   end
-
-  cattr_accessor :plugin_ignore_draft_sequence_callbacks
-  self.plugin_ignore_draft_sequence_callbacks = {}
-
-  def self.invalid_user_id?(user_id)
-    user_id < 0 || self.plugin_ignore_draft_sequence_callbacks.any? do |plugin, callback|
-      plugin.enabled? ? callback.call(user_id) : false
-    end
-  end
-  private_class_method :invalid_user_id?
 end
 
 # == Schema Information
diff --git a/app/models/user.rb b/app/models/user.rb
index d9678d1a1c7..0147c62b1bb 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -306,8 +306,12 @@ class User < ActiveRecord::Base
     fields.uniq
   end
 
+  def self.human_user_id?(user_id)
+    user_id > 0
+  end
+
   def human?
-    self.id > 0
+    User.human_user_id?(self.id)
   end
 
   def bot?
diff --git a/lib/plugin/instance.rb b/lib/plugin/instance.rb
index ab48f7cbead..0390216ebe6 100644
--- a/lib/plugin/instance.rb
+++ b/lib/plugin/instance.rb
@@ -405,15 +405,6 @@ class Plugin::Instance
     SeedFu.fixture_paths.concat(paths)
   end
 
-  # Applies to all sites in a multisite environment. Block is not called if
-  # plugin is not enabled. Block is called with `user_id` and has to return a
-  # boolean based on whether the given `user_id` should be ignored.
-  def register_ignore_draft_sequence_callback(&block)
-    reloadable_patch do |plugin|
-      ::DraftSequence.plugin_ignore_draft_sequence_callbacks[plugin] = block
-    end
-  end
-
   def listen_for(event_name)
     return unless self.respond_to?(event_name)
     DiscourseEvent.on(event_name, &self.method(event_name))
diff --git a/spec/models/draft_spec.rb b/spec/models/draft_spec.rb
index b2066b048de..980f0795998 100644
--- a/spec/models/draft_spec.rb
+++ b/spec/models/draft_spec.rb
@@ -12,6 +12,22 @@ describe Draft do
     Fabricate(:post)
   end
 
+  context 'system user' do
+    it "can not set drafts" do
+      # fake a sequence
+      DraftSequence.create!(user_id: Discourse.system_user.id, draft_key: "abc", sequence: 10)
+
+      seq = Draft.set(Discourse.system_user, "abc", 0, { reply: 'hi' }.to_json)
+      expect(seq).to eq(0)
+
+      draft = Draft.get(Discourse.system_user, "abc", 0)
+      expect(draft).to eq(nil)
+
+      draft = Draft.get(Discourse.system_user, "abc", 1)
+      expect(draft).to eq(nil)
+    end
+  end
+
   context 'backup_drafts_to_pm_length' do
     it "correctly backs up drafts to a personal message" do
       SiteSetting.backup_drafts_to_pm_length = 1