What happens when Apple deactivates your iphone for running iOS7 without a Dev Cert?

I may or may not have managed to get hold of a beta version of iOS7 and I'm not a developer. I may or may not have been able to install it and get it running well on my iphone. I understand that Apple deactivate devices they find running unauthorised copies of iOS7. If that happened to someone, is that it for their iphone? Is there a legal way of reactivating it like if you go back to iOS6 or something?

And if there a way of stopping Apple from seeing you're using a beta of iOS7, such as switching off the Diagnostic and Usage option?

Try running recovery mode. If that doesn't work buy a new phone.