You can always design around that. I know I'm mostly locked in when I deploy a classic GAE application or when I use the datastore (there is AppScale, if you need).
If what you are running is a virtualized version of your physical DC infrastructure, you can probably deploy it anywhere with very little trouble.
We are having A LOT of troubles due to lock in with Google Cloud (particularly GAE and Datastore, but also Pub/Sub) and it is really not fun at all...