Or is this appropriate for any SaaS vendor? You're OK with this? Should all customers, even those who really don't care if the NSA could be watching, be put out because some feel that this cause trumps actually doing business and having customer-vendor relationships?
I could see someone suing an SaaS vendor for an action like this, actually. "You cost me $XX in actual costs and $YYY in lost business. Your TOS says nothing about your shutting down because the government asked you to do something you didn't agree with."