Added warning that running meta_demo.rb can break other things.

meta_demo.rb

@@ -5,6 +5,12 @@
 # Purpose:  Define a simple class that uses ActiveModel::Validations
 #           so WebTools can observe the methods generated by ActiveModel.
 #
+# WARNING:  Running WebTools is safe, BUT RUNNING meta_demo.rb IS NOT!!!
+#           It unsafely persists rubygems, active_model and active_support
+#           in a state that will have unintended consequences.  If you
+#           run it, you should run "maglev force-reload" afterwards to
+#           load an empty database.
+#
 # Usage:    maglev-ruby -Mcommit meta_demo.rb
 #           or
 #           rake meta
@@ -21,9 +27,9 @@
 
 class AValidPerson
   include ActiveModel::Validations
- 
+
   validates_presence_of :first_name, :last_name
- 
+
   attr_accessor :first_name, :last_name
   def initialize(first_name, last_name)
     @first_name, @last_name = first_name, last_name