Maybe. All uploads could be padded with the maximum buffer size so you can't tell the difference. The buffer could flush only small amounts at a time. Some compression algorithm could be used that becomes more efficient with larger recordings.

What you should be asking with any "smart" device is "can I prove this device will do no harm to me".

Honestly I have never understood the value proposition of any smart device. Why would I want any of that functionality? Never once in my life have I ever wanted to talk to my TV. I'm beginning to (again) question the wisdom of carrying a smartphone.