diff --git a/Library/Contributions/examples/brew-fetch.rb b/Library/Contributions/examples/brew-fetch.rb
index 2f7ddc6f80..28606e3fd0 100755
--- a/Library/Contributions/examples/brew-fetch.rb
+++ b/Library/Contributions/examples/brew-fetch.rb
@@ -10,8 +10,19 @@ ARGV.formulae.each do |f|
   end
 
   the_tarball = f.downloader.fetch
-  if the_tarball.kind_of? Pathname
-    puts "MD5:  #{the_tarball.md5}"
-    puts "SHA1: #{the_tarball.sha1}"
+  next unless the_tarball.kind_of? Pathname
+
+  previous_md5 = f.instance_variable_get(:@md5)
+  previous_sha1 = f.instance_variable_get(:@sha1)
+
+  puts "MD5:  #{the_tarball.md5}"
+  puts "SHA1: #{the_tarball.sha1}"
+  puts
+
+  unless previous_md5.nil? or the_tarball.md5 == previous_md5
+    opoo "Formula reports different MD5: #{previous_md5}"
+  end
+  unless previous_sha1.nil? or the_tarball.sha1 == previous_sha1
+    opoo "Formula reports different SHA1: #{previous_sha1}"
   end
 end