Well, yes
This could tempt me to finally buy a smartphone.
KDDI will be the first Japanese mobile carrier to bring Firefox OS to Japan – but its first Firefox OS phone will arrive at an unusual price point for Mozilla's open-source OS: 50,000 yen, or around $415. While most Firefox OS partners have been shipping devices with humble specs at rock-bottom prices, KDDI's entry, dubbed the …
If you're actually going to pull the trigger on this, then do so, and tell me (I might want a PDF of your receipt, being a doubting man).
Speaking for the rest of us - why would you??
Even if you're suitably paranoid, it's not a major problem to root and lock down an android (or I guess iOS) phone, and actually end up with something useful.