I'm guessing this is because they block proxy servers and there are a number running on App Engine.
I'm personally pissed off because I've been using App Engine as a CDN and now a couple of my sites are broken.
Does anyone have a contact at Google SG? They don't pick up their main line and they must have a direct line to the ICT since they censor some search results and youtube videos to comply with Thai laws.
If you have a contact, please ping me at mbenjaminsmith AT gmail DOT com.
Thanks